is predictable, but not the number of highly disturbed days,
ie SCs.
Equinox, solstice variation discussed. Pattern most noticeable for highly
disturbed days. For these days there is a possible assymetry for fall and spring.
The data set is for 1868-1967.
Dst prediction discussed. Possible preference of large storms for descending
phase of the cycle mentioned. The biggest storms (Dst >200 nT) seem to be evenly
distributed over the cycle (small sample).
A short summary of geomagnetic indices.
*Illing and Hundhausen, Disruption of a Coronal Streamer by an Eruptive
Prominence and Coronal Mass Ejection, 1986, [IlHu:86].
KW: CMEs, Structure, Streamers, Eruptive Prominence.
Based on a prominence eruption and CME of August 18, 1985.
Demonstrates the three part structure of, CME front, cavity, and prominence.
Follows the slow expansion of a helmet streamer over several days before the
event, resulting in "an unusually extended (or tall) version of a helmet".
As the event progresses, the front gets thinner and better defined, the core
expands. Comparison of C/P and H alpha data suggest the prominence still cool.
After the event a fan forms, no legs seen. Streamer reformation takes
several days. Suppose that a streamer swelled, erupted, and reformed. The
filament also reformed on disk.
Rise of streamer compared to effects of rotation, which are not sufficient
to account for it. 11hr pause in its rise just before eruption. Front edge of the
CME arc moves slightly slower than the back edge. The prominence positions agree
well with H alpha observations, and was moving significantly slower than the CME.
Mass calculations show: the streamer amd the CME front are essentially the same
mass, 1.1x10x16 g; the prominence has 1.5x10x16 g; and the fan 2.3-7.1x10x15 g,
which is less than the streamer. Conclude streamer mass has not been replaced
from the lower corona. Kinetic energies were: 1x10x31 ergs for both CME and
prominence; while the potential energies were 3x10x31 and 5x10x30 ergs for the
prominence and CME respectively (10x31 ergs for the streamer). Total: 5x10x31 ergs.
Unusual in that prominence mass is as large as the CME. Energy and mass
comparible to the averages for interplanetary shocks. These are usually attributed
to flares, which is not true in this event.
*Tang, The Two Types of Flare-Assciated Filament Eruptions, 1986,
[Ta:86]. RNR
KW: Flares, Eruptive Filaments, Partial Eruptions.
This paper discusses two type of flare associated filament eruptions. One
class involves the eruption of only an upper level filament, leaving the channel
and another filament intact underneath.
1987
*Gonzolas and Tsurutani, Criteria of Interplanetary Parameters Causing
Intense Magnetic Storms (Dst < -100 nT), 1987, [GnTr:87].
KW: Storms, SCs, Shocks, Bz.
A look at the ten large (Dst < -100 nT) storms in 1978-1979. In all cases
there was intense interplanetary B, with Bz being < -10 nT for some period. There
were shocks (or NCDEs) in all cases. Cite strong relation between SCs and shocks.
However for storm strength, best correlation is with the intergral of Bz over
time. No clear relationship between storm magnitude and shock strength. Also looked
for similar Bz + events, found 11. Everything similar except no storms. No IP events
similar to those causing the 10 storms, but without a storm, were found. Correlation
of integrated Bz to peak Dst, is .75. Suggest same sort of solar or IP events give
rise to both +/- Bz events. Mention standard candidates, shock amplification by
high-speed streams, turbulent fields from CIRs, kinky HCS events, magnetic clouds.
*Kurokawa et al., Rotating Eruption of an Untwisting Filament Triggered
by the 3B Flare of 25 April 1984., 1987, [Kuetal:87]. NR
KW: Flares, Flux Ropes, Emerging Flux, Filament Formation, Eruptive Filament.
A paper dealing with the formation of a filament prior to a major flare,
due to emergence of a flux rope. Also the filament eruption after the flare
and its twisting motion, which is said to be consistent with Uchida-Shibata
model.
*Tang, Quiescent Prominences - Where are they Formed?, 1987,
[Ta:87]. RNR
KW: Filament Formation, Quadrapolar.
More prominances are formed between bipolar regions than inside them. The
excess increases at solar maximum. Calls for a new model.
*Tsurutani and Gonzolas, The Cause of High Intensity Long-Duration
Continuous AE Activity (HILDCAAs): Interplanetary Alfven Wave Trains, 1987,
[TrGn:87]. NR
KW: Storms, High-speed Streams, Alfven Waves.
The proposal of long-wavelength Alfven waves in high-speed streams as the
cause of the prolonged activity following the "storms" at the onset of the
streams.
*Webb and A. J. Hundhausen, Activity Associated with the Solar Origin of
Coronal Mass Ejections, 1987, [WbHu:87]. NR
KW: CMEs, Associations, LDEs, Eruptive Prominences.
A repeat of the Munro etal (1979) paper but using the SMM data. Similar
associations of fliament eruptions and LDE with CMEs were found.
1988
*Neugebauer, The Problem of Associating Solar and Interplanetary
Events, 1988, [Nu:88].
KW: CMEs, Storms, Flares, Associations.
This is a good review of all the difficulties involved in making
associations of solar events with interplanetary disturbances. It also
provides a good review of the literature on the subject. The basic problems
covered are: 1) not enough data, 2) too much solar activity, 3) the physics
is too poorly understood.
*Tsurutani et al., Origin of Interplanetary Southward Magnetic Fields
Responsible for Major Magnetic Storms Near Solar Maximum (1978-1979), 1988,
[Tretal:88].
KW: Bz, Causes, Storms.
A study of the causes of large southward Bz during major geomagentic storms
during solar maximum of cycle 21. 10 events with Dst < -100 nT. In all cases Bz was
< -10 nT for more than 3 hours. Several cases are given in detail, more in capsul.
A zoology of IP disturbances, clouds, streams, CIRs. Point out difficulties with
projecting solar AR orientation to Earth for storm studies.
1989
*van Ballegooijen and Martens, Formation and Eruption of Solar
Prominences, 1989, [BaMn:89]. RNR
KW: Filament Formation, Eruptive Filaments, Model.
A numerical model based on the inflow to the inversion line is found
to produce helical "filament" structures. Their stability and eruptability
is explored.
*Kahler, Sheeley, and Liggett, Coronal Mass Ejections and Associated
X-ray Flare Durations, 1989, [KaSeLg:89]
KW: CMEs, Flares, Radio, Correlations, Solwind.
The probability of flare association with a CME increases with flare duration.
A graph of association percentage vrs flareduration is given (from Sheeley etal.
1983). This paper looks at the association of short duration events with CMEs.
Flares selected (subjectively) with impulsive profiles and H alpha flare signature
> 40 degrees from central meridian. They checked Solwind data from .5-2 hrs after
the peak of the flare. Note this is a surprisingly short window. Of 77 events 14 were
clearly associated, 51 clearly not; 22%. Table compares with and without classes.
Those with CMEs were more energetic and faster than average (though not fast for
energetic flares). Narrow angular widths (for energetic CMEs). Comparison with
radio data also given.
Next surveyed all Solwind CMEs; selected associations with M and X flares, and
H alpha within 50 degrees of the limb. Linear extrapolation of CME velocity gives
start time differences of upto 40 minutes (63 events; 67% within 22 minutes). The
limb projected angular seperation of flare from CME center was upto 55 degrees.
The impulsive flares were tighter in space and time. Full flare duration correlates
better (.66) with CME width than the duration of the main peak (.40). Fairly large
errors analized. Better correlation with flare decay (0.67) than rise (0.46).
Speeds do not correlate well. Inverse correlation between CME association and
flare duration (??? a problem with selection??). Associated flare and radio
statistics given for wide and narrow CMEs. Analysis of angular separation; wide
distribution, from centered to outside the legs (non-radiality with altitude not
accounted for). Associations with filament eruptions and post-flare loops given.
Suggest that impulsive flares with CMEs are not an essential part of the CME
process. Also that filament eruptions from impulsive flares are contained in the
corona.
Conlude two classes of CME associated flares: LDEs which are fully eruptive,
and impulsive flares that are contained. This latter class expected to be large.
Deduce that the event length CME width correlation is due to event volume CME
width correlation (even though the scales are quite different). Discussion of
reconnection model, and Harrison's association with the CME feet; both considered
to be wrong.
*Martin, Mass Motions Associated with Solar Flares, 1989, [Mr:89]
KW: Flares, H alpha, Ribbons, Surges, Filament Activation, Eruptive Filaments.
A review of the motions seen after two ribbon flares, mostly H alpha. A
detailed discription flows associated with the ribbons. Comments and references
on remote brightenings. Discussion of post-flare loops including comments and
references on Skylab x-ray work. Outlines downflows, and upflows in the different
phases. Discussion of flaring arches, something like compact versions of Shibata's
jets?? Discussion of surges. Examples of different filament activations given,
pre-eruptive, surge-like, and impact activation. References to specific treaments.
A nice whip-like upper-level (Tang-like) eruption shown. An example of multiple
eruptions and remote activation of a third filament. Discussion of Halpha "CMEs".
Probably relevant to the Yohkoh "CME"s. Brief references to Morton waves, and
remote brightenings again.
1990
*van Ballegooijen and Martens, Magnetic Fields in Quiescent
Prominences, 1990, [BaMn:90].
KW: Filaments, Fields, Solar Cycle.
An examination of the measurements of prominence axial field direction. In
particular an analysis of the effects of differential rotation on inversion lines
and thus prominence fields. They find that for inversion lines close to vertical,
greater than 45 degrees, differential rotation produces the result that Martin
and McAllister would predict. However, for smaller angles (more nearly horizontal)
to opposite is true. Initially, even for small angles, the results are consistant
with differential rotation, but after a time it reverses. Since they feel most
neutral lines are roughly east-west they feel a new explanation is called for.
This is inspite of suggesting that the field is fixed and frozen in early on when
the neutral lines are mostly vertical. A picture of a convoluted neutral line is
given.
They propose that the flux emerges from below the surface where differential
rotation acting on the return portion of the loop (if it is a helix) gives the
right sign of field (after its raised into the chromosphere).
*Cliver, Feyman, and Garrett, An Estimate of the Maximum Speed of the Solar
Wind, 1938-1989, 1990, [ClFyGa:90].
KW: Solar Wind, Velocities, Great Storms, CME Proxies, Associations.
A review of great storms from 1938-1989, looking for the highest solar-
terrestrial propegation times. Good collection of references; sources of
statistics, and for associations and correlations. The methodology was to
look at severe storms, then look for proceeding proton flares, use the proton
flare and a subsequent sudden commencement (SC) to give a shock transit time,
and finally adjust this speed by an empirical formula to get the peak flow
velocity.
Previous event associations have had problems (cites Neugebauer, 1987).
The highest speed events associated with flares (coronal hole high speed streams
are never observed at Earth at over 1000 km/s, and DB associated events are also
generally slower than the largest flare events). They specifically target solar
energetic proton (SEP) flares, because of consistent association with high
speed CMEs (cites Kahler et al. 1984). SEP peak fluxes correlated with CME
speed. They use large-SEP events as proxies for high-speed CMEs. Correspondence
between CMEs (at least fast ones) and shocks. Finally assocaition of SCs and
shocks (Smith et al. 1986). IP type II bursts associated with SEP flares and
high speed CMEs.
Started with 138 events with Ap* over 100, sort down to 22 events with
good identification. Note that identifying terrestrial proton events with
flares is easier than for storms, as the transit times are ~1.2 hrs. There
are occasional proton events without obvious flares. Detailed discussion of
the association and identification procedures. Selected flares turned out to
be clustered near CM, consistent with studies indicating major storms are
mostly launced near disk center. Mostly looked at longer duration events.
Frequent Type IV bursts.
Focus on 6 events with transit times of up to about 20 hours. Points
out that fast transit events do not always have large SCs, contrast is more
important than absolute speed, so SCs in slow wind backgrounds are often
larger (also more mass).
Gives empirical formula Vmax = 0.775Vshock - 40 km/s where V shock is
the average transit time for the shock. Median delay between SC and Vmax
for 29 high-speed events was 5 hrs (Cane, 1985).
August 4, 1972 had a peak flow of over 2000 km/s. There were four
others over 1500 km/s. List of other historical fast events given. Some
shocks over 3000 km/s have been observed. Some evidence that for repeat
CMEs, the foloowing ones move faster, references given.
*Gosling et al., Coronal Mass Ejections and Magnetic Flux Ropes in
Interplanetary Space, 1990, [Goetal:90]. NR
KW: CMEs, Flux ropes.
*Harrison et al., The Launch of Solar Coronal Mass Ejections: Results from
the Coronal Mass Ejection Onset Program, 1990, [Hnetal:90]. [finish reading]
KW: CMEs, Drivers, Correlations, Timing.
Results of a study combining instruments on SMM to look for x-ray signatures
of CMEs. Admittedly biased to flares. Characteristics: 10x30-32 ergs, 10x15-16 grams.
Cite associations with flares, filaments, ARs, still targeting ARs. Result in large
scale coronal changes. Estimate of visibility in white light away from the limb;
50% at +/- 51 degress. Spot CMEs with the coronagraph, project back to disk and then
try to locate what was there. Although the CME front forms in SMM field of view,
origins believed to be lower. They declare deceleration of CMEs after launch, but
before SMM sees them unlikely.
Review of CME theories; thermal and magnetic drivers. List several problems with
the thermal concept, but do not rule it out. Several magnetic scemes listed, CHSKP
based (not much done with these); discussion of prominence driven models (velocity
inconsistancies); cavity driven models (possible giving rise to some x-ray signature
at launch); comes full circle to CME leading to flare.
Outline of instruments involved in the program. Found 16 events (this was 85-86,
nearly at minimum). Wide spectrum of x-ray event types, break into minor and principle
events. Mentions previously proposed relationship to LDEs, but ignore this, though
they do list a "gradual rise and fall" events type?
For 75% of events a bright core was observed by the coronagraph. Apparently 14/16
had some sort of H alpha activity, mostly prominence eruptions. Streamer tip locations
tablulated. The scale of CMEs can cover more then one AR, program biased to ARs. 8/16
had one AR, 6/16 had two. A histogram shows most were equatorword of the middle of the
CME loop. Possibly solar cycle effect.
The two events without x-ray activity were related to ARs 20 degrees behind the
limb. These were all principle events.
*Soru-Escaut and Mouradian, Sudden Disappearance and Reappearance of Solar
Filaments by Heating and Cooling, 1991, [Goetal:91]. RNR
KW: Filaments, Thermal DBs.
Discussion of the concept of thermal DBs. Several examples given.
1991
*Gosling et al., Geomagnetic Activity Associated with Earth Passage of
Interplanetary Shock Disturbances and Coronal Mass Ejections, 1991, [Goetal:91].
KW: Storms, CMEs, Shocks, Bz, Solar-Terrestrial.
A look at the geo-effectiveness of shocks and CMEs (1978-1982). ISEE 3 data for
this period include 191 counterstreaming electron events (CSEE) (minus those due to
Earth's bow shock), equated with CMEs. They averaged 3.9 per month (solar cycle max),
lasting an average 18 hrs, to make up 10% of the data. For shocks, 151, 3.4 per month.
32% of CSEEs had a shock out front (within 24 hrs), but 36% of shocks had CSEEs behind
(within 24 hrs). Conclude i) many slow CMEs, ii) shocks are often broader than CMEs.
Stats on association of storm size categories with CMEs and shocks given (pie charts).
Almost all large and major storms (Kp > 7-) believed to be associated with shocks
driven by CMEs, (1 out of 37). The majority of smaller storms had other origins.
Defining geoeffective as Kp > 5-, 44% of CMEs and 53% of shocks were geoeffective.
Plots given showing Kp distributions for all data, CME, shock, and CME/shock
data. CME/shock most effective. Also as percentages of a given Kp value. Plots
of velocity, magnetic field strength, and Bz versus storm category. Large storms
associated with fast moving strong fields. Direction only slighty skewed to
south, but all large storms have periods of strong Bz south. Large and major
storms regularly have B above 10 nT.
These results for solar maxiumum. Expect high speed streams to dominate near
minumum. Velocity differential, which leads to shocking and flux pile-up etc.
deamed most important.
*Harrison, Coronal Mass Ejection, 1991, [Hn:91].
KW: CMEs, Properties, Correlations, Models, Review.
A review of CME characteristics and analytical models. A nice list of
properties and associations. Thermal/flare driven models dismissed. Prominence
driver models also not viewed favorably. The general discussion points out
problems with almost all the models, mostly due to over simplification. A
cartoon is presented with various scales included.
*Schmieder et al., Conditions for Flare and Filament Formation in
Interacting Solar Active Regions , 1991, [Scetal:91]. NR
KW: Flares, Filament Formation, Quadrapolar.
Flaring and filament formation in two interating active regions.
*St. Cyr and Webb, Activity Associated with Coronal Mass Ejections at Solar
Minimum: SMM Observations from 1984-1986, 1991, [CyWb:91]. NR
KW: CMEs, Associations.
Measured CME speeds extrapolated back to the lower corona and associations
within 45 degrees longitude and 30 degrees latitude, +/- 90 minutes tabulated.
73 events during solar minimum were examined.
*Vrsnak et al., Stability of Prominences Exposing Helical-like
Patterns, 1991, [VrRuRm:91]. NR
KW: Filament Structure, Fields, Helicity, Eruptive Filaments.
Measurements of the twist of quiesent and erupting prominences were made.
Rough agreement with length and twist cutoffs for eruptives based on theory
was obtained.
1992
*Kahler and Hundhausen, The Magnetic Topology of Solar Coronal Structures
Following Mass Ejections, 1992, [KaHu:92]
KW: CMEs, Post-Event, Streamers, Transient Holes, Radio.
A study of Post CME structures seen in white light coronographs.
Features are devided into legs and streamers. Mostly focusing on 1984-1987 SMM
data. 3 classes of legs defined. Only 2/16 CMEs show classic double leg profiles
after the eruption. Post CME structures usually look like new helmet streamers.
Legs fade in half a day, then new streamers appear. Some notes on transient coronal
holes and on type IV radio bursts.
*Kubota, Kitai and Uesugi, The Sudden Disappearance of a Dark Filament
Observed on October 26, 1989, 1992, [Kuetal:92] RNR
KW: Eruptive Filaments, Mass Motions.
A filament eruption is reported in which the filament apparently consists
of two parts, which separate prior to the eruption and show different velocities
during the eruption.
*Martin and Livi, The Role of Cancelling Magnetic Fields in the Buildup
to Erupting Filaments and Flares, 1992, [MrLi:92]. RNR
KW: Filaments, Emerging Flux, Cancelling Flux, Eruptive Flares.
Discussion of the observations of flux cancellation along inversion lines
and its role in creating the axial component of the filament field, and in
leading up to flares and eruptions.
*Martin, Marquette, and Bilimoria, The Solar Cycle Pattern in the
Direction of the Magnetic Field Along the Long Axis of Polar Filaments,
1992, [MrMqBi:92].
KW: Filaments, Structure, Solar Cycle.
This paper discribes two techniques for determining the direction of the axial
field along a filament channel of filament. The first uses the plagettes, the second
the feet of a quiesent filament or prominence. They agree with each other for all
cases tested. These techniques are applied to filaments in 1989 and 1991 to extend
the pattern of polar crown axial fields to cycles 21-22 and 22-23. With the Rust
results, and Leroy's results, this gives four cycles. In all cases the sub-polar
crown channels have the opposite field. The pattern is: north, westward; south,
eastward, for cycles 19-20 and 21-22, and visa versa for cycles 20-21 and 22-23.
Fibril assymetry is not found beneath some high filaments in weak field areas.
*Sheeley, The Flux-Transport Model and its Implications, 1992, [Se:92,].
KW: Flux Sources, Differential Rotation, Solar Cycle.
A brief discussion of the flux-transport model with differential rotation,
meridional flows and diffusion. Useful references to earlier work on rotation
rates of various features, and to the full papers on the FT model. An update
of Leighton's 1964 model but with the meridional flows. Finds average 10 km/sec
poleward, but needs more during some periods to match observations. Effective
diffusion rate of 600 km2/sec.
Data from cycle 21. Single flux region: grew over several weeks, then
fades, diffuses, shears etc. Supergranular structure ~30,000 km scale, with
flux confined to cell boundaries. Diffusion approximation holds only for scales
large compared with the supergranular scales (both spatial and temporal). Thus
it can't match the high latitude Snodgrass rates.
The salt and peper do not contribute to the large-scale field discribed by
the FT model. Discusses necessity for meridional flow. With a strong diffusion,
leading spots cross the equator and cancel, trailing spots migrate to the poles.
Using observered active regions as sources (2500 over 1976-1984) took a year or
two to begin to match well. For the polarity patterns (mean field) only the
largest spots (about 300) contribute, and little sensitivity to diffusion rate.
Decays by being wound up by differential rotation. The gross field (averaged
absolute field) depends on the small scale and highly dependent on diffusion rate.
Discussion of rotation rates. The quasi-rigid rates (photospheric large-scale)
due to the interaction of diffusion and meridional flows to move flux latitudinally.
Coronal rates studied in context of source surface models, due to rapid falloff of
high order field modes of potential field. [Of course there are some problems with
this assumption]. Discussion somewhat vague. Reference to coronal holes drifting
across unipolar field regions, only shearing when they hit the boundaries (ie.
neutral lines)?
*Snodgrass, Smokestacks and Balloonmen: A Magnetic Rotation Controversy,
1992, [Snd:92,].
KW: Flux Sources, Differential Rotation, Solar Cycle.
Differential rotation profile determinations. Snodgrass 1983: 1-4 day
cross-correlation, same as photospheric rates. Autocorrelated daily maps give
flatter high latitude profiles. Cross-correlation of synoptic maps also gives this,
with variation over the cycle. Later Stenflo (1990) repeats autocorrelation, finds
flattening but no variation. Posit differences due to temporal filter of days vrs.
rotations. Sheeley and Steflo models for this with large-scale and small-scale
components, but different flux sources; diffusion, vrs continued emergence. Recently
redone the crosscorrelations of magnetograms but with long time delay, yields
roughly the same profile everytime. So differences must lie elsewhere, not in time
selection.
Outline of smokestack (Sheeley et al.) model and balloonman (Stenflo) model.
Proposes spatial resolution rather than time lag as the selection parameter. A
nice outline of the different methods, and analysis of how the crosscorrelation
focuses on the smallest resovable scale, while the resolution of the auto-correlation
is fixed by the sampling rate. Shows difference between AR belt and polar auto-
correlation analyis, the former resolving features, the later with much noise from
smaller unresolved features. Both scales seen (to some extent) in each method, and
time-scales comparable. Comments on the Carrington map analysis, smears small scales
at high latitudes, tend to see larger features.
Long time-scale for small features hard to explain in diffusion model. Diffusion
of 500 km2/sec would disolve medium scale features in days. Note: magnetic and
super-granular rotation rates are separate. Deeply rooted flux would resist motion
of surface features (Wilson et al., 1990). For Stenflo the problem is to build up
the large scale patterns from the small scale, detatched, balloons. Some simple
examples tested and failed.
*Stenflo, On the Validity of the Babcock-Leighton Approach to Modeling the
Solar Cycle, 1992, [Stn:92,].
KW: Flux Sources, Differential Rotation, Solar Cycle.
Discussion of the emergence of flux in ephemeral regions (ER) and intranetwork
fields (IN) as well as active regions (AR). Averaged over the sun, rates of emergence
are: AR, 10e20 Mx/day; ER, 10e22 Mx/day; and IN, 10e24 Mx/day. Latitude distribution
increases and orientation randomizes with *decreasing* scale. The IN fields emerge
at a rate that is twice in a day what the ARs produce in a cycle! Makes the distinction
between pattern phase velocity and plasma velocity. Refers to Snodgrass study (1983)
or high latitude pattern correlation. Scale of 1'x1', 5 times SG scale (in part due
to projection). Result in high rotation rates than diffusion models give. Claims this
result must be due to the collection of ongoing small scale emergence. The phase
velocity is close to photospheric plasma velocity.
Autocorrelation time series analysis of large scale structures. Nearly constant
speed at equator over the cycle. Peaks broaden towrds the poles. Power is distributed
evenly at low latitudes, but restricted to the m=1 at high latitudes. Global component
quasi-ridgid, intermediate scale not. Proposes a two component model, large-scale
fields are flux transported, small scale average out. This depends on random,
isotropically oriented small scale emergence. Claims ERs show distinct average tilts,
and that longitudinal variation may occur (as for ARs). Even small patterns are
magnified by the large amount of flux. Again for IN even small deviations have a
very large effect. Conditions at this scale are not known. Claims that the lack
of change in quasi-ridgid rotation over the cycle is a problem. But I thought Don's
work showed that the curves do change?
Postulates, that the local bits move with the photospheric rates (Snodgrass)
but that there are "active longitudes" all the way to high latitudes, and that these
drift with the global rates and by greater emergence rates dominate longitudinal
averages. Distinction made between crosscorrelation and autocorrelation, these gives
similar results at low latitudes, but differ at high latitudes. The high latitude
phase velocity matches the helioseismology results for the bottom of the convection
zone.
*Tsurutani et al., Great Magnetic Storms, 1992, [Tretal:92,].
KW: Storms, Causes.
An examination of the five largest storms from 1971-1986, Dst from -249 nT
to -325 nT. Concludes that while both velocity and Bz magnitude are important,
Bz magnitude is primary. Both shocked gas with field drapping (higher speeds, 3),
and magnetic clouds (lower speeds, 2) were found. All associated with flares (and
assumed CMEs). A long duration south Bz precursor important for large storms.
Dst better storm index than Kp and Ap. Average ecliptic solar wind 468 km/sec,
with standard diviation of 116 km/sec. Probabilites of large Bz: > -20 nT, 4.3e-4;
-30 nT, 7e-5. These storms all had Bz from -25 to -35 nT.
1993
*Bame et al., Ulysses Observations of a Recurrent High Speed Solar
Wind Stream and the Heliomagnetic Streamer Belt, 1993, [Bmetal:93].
KW: Solar Wind, High Speed Streams, Streamers, Ulysses.
Discription of the high speed stream from the south polar coronal hole, 14 passages
through June 1993 (S34). Low-speed high-density stream from the heliomagnetic streamer
belt. This fades after April 1993 (S29), average speeds increase and average density
decreases (factor of 2.5 over 24 degs). Also IMP8 data. Variations in the ecliptic
highly damped. Ulysses CME Nov. 10. 1993 (DOY 314). Trace eastward migration of SPCH.
[Check specific values].
*Bravo, The SC Event of 6 June 1979 and Related Solar and
Interplanetary Observations, 1993,
[Adv. Space Res. 13, 9, 371-374].
KW: Solar Wind, Storms, Coronal Holes, HSS.
Suggests that IP shocks may be caused by changes in coronal hole
boundaries associated with CMEs, rather than by the CME itself. The
opening of the region under a CME is supposed to create a less divergent
open field, which should have a faster wind. IE a part of the slow
wind is converted to fast wind, producing a shock at the interface. The
shock and the CME are supposed to originate in tandum but not be
themselves causally related.
*Cliver and Crooker, A Seasonal Dependance for the Geoeffectiveness of
Eruptive Solar Events, 1993, [ClCr:93].
KW: Solar-Terrestrial, Seasonality, Problem Storms.
Seasonal dependancy of geomagnetic activity due to enhanced magnetopause
coupling. Problem storms are promenently addressed and several examples are
shown to have been associated with large filament disappearences.
*Crooker et al. Multiple Heliospheric Current Sheets and Coronal
Streamer Belt Dynamics, 1993, [Cretal:93]
KW: Solar Wind, CMEs, HCS.
This paper proposes that A broad heliospheric current sheet (HCS) is
made up of many smaller current sheets, reflecting a multiple current
sheet structure of the streamer belt at the sun. Lots of good references.
The HCS, an extension of the solar streamer belts, shows complex
structure in interplanetary space. Reviews attempts to measure the orientation
of HCS crossings, mostly by minimum varience analysis. Suggests that
treatment of the whole series of discontinuities gives an average orientation
for the whole slow speed stream, but that there are many variously oriented
interfaces with in this span. The thick sheet oreientations are close to
that expected from the Parker spiral, with inclinations matching those of
the underliying neutral line at the sun (source surface maps). Individual
boundaries have normals from ortho-Parker to radial. Review of work on
field rotations, with interpretations as clouds, sector boundary crossings,
and planar magnetic structures. These may all occur near the sector boundary
and can be difficult to distinquish.
Discribes the idea of streamers with multiple current sheets. This seems
overly complex, though the basic idea may have some application.
Discusses the rotational signatures of erupting arcades, both met head
on and as the expand outwards to the side. The later produces a signature
like a magnetic cloud (180 degrees). Use of the term skew. The multiple CS
model can lead to planar structures by (1) multiple eruptions with different
orientations and met sideways would give PMSs, (2) A single CME can push
the various CSs to the side.
Reviews possibility of unsteady streamer outflow. This is said to vary
as much as 50% between limb passages. More convincingly, changes during single
limb passages (not CMEs) have been observed. Again mentions small closed
tongues (Uchida et al. ?). Objections to this idea: lack of bi-directional
streaming, and flux buildup problem (seems to imply reconnection near the
Sun).
Overview: "Implies that the heliospheric current sheet is not a single
surface but a constantly changing layer with a varying number of current
sheets of finite extent filing the finfite thickness of the coronal streamer
belt". This forms a conduit for CMEs, which occur mainly near the streamer
belt (Hundhausen, 1993).
Detailed case study of a specific sector boundary crossing (April 21,
1979) observed near Earth (ISEE 3) and at 0.5 AU by Helios 2. Matches
closely to a general crossing profile (non CMEs) created by super-posed
epic analysis for declining phase data. This shows a density spike at the
crossing (steeper on the front side), a slow velocity drop into the crossing,
followed by a steeper and longer rise, and a simliar slow drop, then steep
rise in the proton temperature. In the specific event there is also a spike
in the density down stream at Helios 2, interpreted as a CME. This was not
clearly seen by ISEE 3. Detailed analysis showed various interfaces (indicated
by field rotations) within this overall structure. Only a few can be directly
associated between the two data sets, implying evolution. The downstream
planar structures seen by ISEE 3 (but not Helios 2) are thought to be the
trailing legs of the CME seen by Helios. The overall orientation of the
layer matches well with Parker spiral and solar NL values.
Discusses "sandwiches" and give references. These being the small scale
regions between the rotational discontinuities. Also referes to "magnetic
holes" seen at sector boundaries (Klein and Burlaga, 1980). Some of these
jumps also show in the temperature. In this event density and B tend to
anti-correlate. Propose this sandwich structure occurs following CMEs,
as it has been seen in the position in the solar wind.
Solar wind turbulance has also been proposed as a source for these
structures. The alternate explaination that one sees multiple crossings
of a single current sheet is hard to match with the overall steep angle.
*Gosling, The Solar Flare Myth, 1993a, [Go:93a].
KW: Solar-Terrestrial, Storms, Flares, CMEs, Flux Ropes, Particles.
A review of the relation of geomagnetic storms to solar flares and CMEs, concluding
that CMEs produce the large storms. First the history of flare association research,
and the definition of the "myth". Then a presentation of CME research, in particular
the lack of correlation with ARs and the class of all flares; observations of CMEs
in interplanetary space, and the flux rope idea; the relation of CMEs and shocks to
large geomagnetic storms (pie charts). A discussion of Solar particle events, which
are of two types, impulsive and gradual. The former are associated with flares, the
latter with CME driven shocks. Presents a "new" paradigm and suggests that flare
folks stop using geomagnetic storms as a justification for flare research. This last
bit is what seems to have cased all the fuss.
*Gosling et al., Counterstreaming suprathermal electron events upstream of
corotating shocks in the solar wind beyond ~2 AU: Ulysses, 1993a, [Goetal:93a].
KW: Counterstreaming electrons, CIRs.
Counterstreaming suprethermal electrons from corotating shocks (14). Typically
form beyond 2 AU. These have a nice two-step velocity profile, and enhanced central
density. Unlikely to be seen at 1 AU, except for remnants of backstreaming electrons.
*Gosling et al, Latitudinal variation of solar wind corotating stream
interaction regions: Ulysses, 1993b, [Goetal:93b].
KW: CIRs, Solar Wind, High Speed Streams, Shocks, Ulysses.
Changes in corotating interaction regions with latitude. Outline of high speed
stream and changes after April 1993. Absence of forward shocks south of S26, whereas
they were dominant equatorward. Shock strength also decreasing. Meridional flow of the
shocks, forward; west, anti-sunward, equatorward, reverse; east, sunward, and poleward.
*Hiei, Hundhausen, and Sime, Reformation of a Coronal Helmet Streamer by
Magnetic Reconnection after a Coronal Mass Ejection, 1993, [HeHuSi:93].
KW: X-ray, White Light, CME, Arcade, Prominence Eruption.
The report on the January 24, 1992 CME and Yohkoh arcade. This was the first
clear case where a CME was seen in whitelight and also observed in Yohkoh. There
was also a large erupting prominece. The reforming helmet in whitelight matched
very nicely the outline of the SXT cusped loops. A faint trace in x-rays associated
with the prominence, hours before the reforming arcade appears.
*Hundhausen, The Size and Locations of Coronal Mass Ejections: SMM
Observations from 1980 and 1984-1989, 1993, [Hu:93].
KW: CMEs, SMM, Properties, Bugles, Corona.
Main paper presenting SMM CME measurements of wide and latitudinal distribution.
Statistics on ... . Result that for 1984 nearly all CMEs were associated with the
streamer belt and appear as bugles in the synoptic plots.
Appendix detailing the geometry of the WL observations.
*Jackson, Remote Sensing Observations of Mass Ejections and Shocks
in Interplanetary Space, 1993, [in Eruptive Flares ed. Svestka and Jackson].
KW: CMEs, Shocks, Solar Wind .
Cited by Crooker etal, 1993: The number of CMEs per unit mass increases
exponentially with decreasing mass.
*Richardson and Cane, Signatures of Shock Drivers in the Solar Wind and
Their Dependence on the Solar Source Location, 1993, [RiCn:93].
KW: Solar Wind, Shocks, Drivers, Radio, Draping.
Study of IP shock driver signatures and the statistics vrs the loaction of the
associated Solar event. Events closer to CM have more observed signatures.
Enhanced B more frequent from eastern events, as the field is most compressed
around the western end of the driver. Driver longitudinal width distribution
(up to 100 degs) similar to twice the SMM latitudinal distribution. Energetic
shocks (w/ type II bursts) NOT driven by magentic clouds.
*Smith et al., Disappearance of the Heliospheric Sector Structure at
Ulysses, 1993, [Smtetal:93].
KW: Solar Winds, Sectors, HCS, Ulysses.
Report on the passage of Ulysses south of the HSC (and the two sector structure)
in July 1993. Previous structure outlined; domination by the south polar coronal
hole. Comparisons with Stanford Source Surface mapping of the HCS naturally have
problems. Predictions are too far south. Conclusion that the deviation from the
potential is outside 2.5 SR is wrong.
1994
*Alexander et al., The Large Scale Coronal Eruptive Event of
April 14, 1994, 1994, [Aletal:94].
KW: CME, Dynaimc Arcade, Physical Properties.
An overview of the April 14, 1994 arcade event. Temperature and emission
measure derived. The emission measure peaks 2-3 hrs into the event, but the
temperature peaks 6-7 hrs into the event. An energy budget is calculated. The
conductive losses dominate the radiative losses, enthalpy loss (mass flux) is
not considered but might be significant if velocities of 100 km/s are reached.
Suggest the necessity of ongoing energy input, or release. He I 10830 ribbon
seperation calculated. The outer edges expand faster than the inner; speeds
vary from 0-2.5 km/s, averaging 1.28 (outer edges) and 0.68 (inner edges).
The coronal hole changes lasted for at least 5 days.
*Bravo and Perez-Enriquez, Coronal Mass Ejections Associated with
Interplanetary Shocks and their Relation to Coronal Holes, 1994,
[Revista Mexicana de Astronomia y Astrofisica, 28, 17-25].
KW: Solar Wind, Shocks, CMEs, Coronal Holes.
Although shocks CMEs are associated with CMEs (but not all CMEs have
shocks), the correlations of speeds is said to be poor. Correlation of CMEs
with "explosive" events is incomplete. Suggest that CMEs are essentially
coronal processes. Cite studies showing that IPS observed IP disturbances
track back to regions that contain coronal holes (Hewish and Bravo, 1986).
Studies of shock correlation with flares and filament eruptions, and with
coronal holes indicate better correlation with coronal holes.
This work based on 49 Solwind CMEs with confident Helios 1 shock
associations, 1979-1982. Mostly low/mid latitude events. 49% had associated
eruptive event, while 70% had coronal hole associations, Used a +/- 30 degrees
in longitude for the CH associations. Histograms of longitudinal distance to
nearest feature X; tightest with coronal holes, then active regions (this is
max), then eruptives. Refer to a propegation of coronal holes to the equator
at minimum, and note that at max the small low/mid latitude CHs have to provide
much of the solar wind.
Claim the CH association is good for CMEs that produce shocks, but not
for other CMEs. Conclude the CH is integral in producing the shock This is
the *main point*. Present the theory that the opening of the corona next to
a coronal hole by a CME causes a shock. [Then what about April 14, 1994??].
*Cliver et al., Rotation-averaged Rates of Coronal Mass Ejections and
Dynamics of Polar Crown Filaments, 1994, [Cletal:94].
KW: CMEs, Filaments, Polar Crown, Solar Cycle.
A nice paper pointing out that there appears to be jumps in the CME rates
timed to changes in the polar crown and sub-polar crown filaments. These jumps,
one down in March 1982 and one up in October 1988 correlate with the passage
of the tilt of the HCS (streamer belt, ala Hoeksema) through 50o. This is the
general latitude that the polar crown resides at through most of the cycle,
except when it is rushing to the poles and the new one is rebounding. These
changes are compared to McIntosh's plot of the maximum latitude of the polar
crown and sub-polar crown filaments from 1974-1992. The steps are aligned about
one year after the old polar crown vanishes and about a year after the polar
crown starts moving poleward, at the time that the sub-polar starts a coherent
polarward movement. It is suggested that a similar change occured in 1978 when
it was correlated with the onset of cosmic ray modulation (presumably by CMEs).
A disproportional change in the large scale CME rate occured in late 1988, and
the high latitude CMEs contributed 37% of the overall increase.
The fact that the CME rate seems to rise after the sub-polar crown starts
to move, suggests that compression of the polar fields (movement of the polar
crown) is not sufficient, but that the topological changes required, and/or
the convergence of opposite polarities, due to the movement of the rising
polarity band is what triggers the increase.
*Crooker and Cliver, Postmodern view of M-regions, 1994, [CrCl:94].
KW: Solar Wind, Coronal Holes, CIRs, CMEs, Seasonal Effects.
This paper reviews the history of the study of recurrent storms and the
search for the "M-regions" that were postulated as their source. It then goes
on to propose that M-regions (or the source of recurrent storms) are not simply
coronal holes but rather the boundaries of holes and the streamer belt, with
CMEs thrown in for good measure.
Refers to strong magnetic fields following sector boundaries, due to the
compression at the leading edge of high speed streams. Illustrated by the Dst
data from 1974: the recurrent low level activity is due to the coronal holes
(Alfven waves, ala Tsurutani and Gonzalez, 1987), modulated by the Russell-
McPherron seasonal effect. The peak activity at the sector boundary crossings
is due to CIR compression and CMEs.
For CMEs: cite the occurrance of CMEs in the streamer belt, thus near
sector boundaries; that sudden commencement shocks (also clustering around
the sector boundaries and often preceeding the recurrent storms) are mostly
from CMEs inside 1 AU; they provide southward IMF which can be compressed in
the CIRs (this compression most effective on slow CMEs); the tails of the
CMEs can increase the flux along the Parker spirial, which is effect with the
season ala Russell-McPherron.
Discussion of the Russell-McPherron effect, and its interaction with
CIRs and CMEs. Compression on the leading edge of the streamer belt behind
fast CME shocks and on the trailing edge in CIRs.
*Gosling, Coronal Mass Ejections in the Solar Wind at High Solar Latitudes:
An Overview, 1994, [Go:94].
KW: ICMEs, Ulysses, Review.
Summary of work in other papers. The Ulysses high latitude CMEs discussed,
velocities shown for all six. Full data given for three cases, June 11, Aug. 29, 1993,
and April 20, 1994. Main focus on CME speeds and the fact that these high latitude cases
are all at the high spped of the background solar wind. Comparison with ISEE 3 data for
a slow CME at Earth orbit (1979). No indication the high latitude CMEs were pushed. This
also appears true for ecliptic CMEs, even the slow ones. Hypothesize that CMEs are, when
launched slower than the solar wind, accelerated by a similar process to solar wind
speeds, at all latitudes. The origin of interplanetary flux ropes discussed. Large
arcades reconnecting with shear could produce these, but not all cases seen at Ulysses
seem to be flux ropes, e.g. April 14, 1994. Over-expansion presented, with the 1-D
simulation results (but with initial over-pressure given as 4). Results also presented
for a 1 AU run with an initial velocity pulse (275 to 980 km/sec for 6 hours),
illustrating the different resulting pressure profile. Suggestion that the reverse
waves could run back to the Sun and be seen as Morton waves.
*Gosling et al., A forward-reverse shock pair in the solar wind driven by
over-expansion of a coronal mass ejection: Ulysses observations, 1994a,
[Goetal:94a].
KW: ICMEs, Shocks, Flux Ropes, Ulysses.
Over expansion shocks from CMEs at high latitude. June 11, 1993 event. Constant
velocity slope (in reverse sense to CRI changes), depleated density. Identified
with May 31, 1993 SXT east limb event. Ulysses near [E90 S32.5]. Flux-rope
formation. 1/3 of CMEs have LDEs, also 1/3 associated with flux ropes.
Simulation: density up by 10, bell-shaped pulse 10 hrs wide, temperature constant,
velocity decreasing from 700-600 km/sec (applied at .14AU, 30SR). Expansion slows
by 4 AU. Results at 4 AU (shock strength and density depletion) depend more on
the pulse size than its duration.
*Gosling et al., The speeds of coronal mass ejections in the solar wind
at mid heliographic latitudes: Ulysses, 1994b, [Goetal:94b].
KW: ICMEs, Properties, Ulysses.
Speeds of high latitude CMEs seen by Ulysses; June 11, July 21, August 24, August 28,
September 5, and October 12, 1993. Velocity data for all. Full data for August 28.
Also data for January 8, 1992 (Ulysses at 5.14 AU, S5.9). Events identified as CMEs
by counterstreaming electrons. Three also have other CME signatures. The June, July,
and 2nd August events had declining velocities (expanding), lowest proton denisties,
and cleanest magnetic field signatures.
Both low and mid latitude CMEs have at least the background Solar wind speed, and
appear to be along for the ride. Suggest that accelleration of slow CMEs and the
normal solar wind are done by the same process, which takes place beyond 6 SR.
*Gosling et al., A new class of forward-reverse shock pairs in the solar
wind, 1994c, [Goetal:94c].
KW: ICMEs, Overexpansion, Ulysses.
Discussion of over-expansion events. 9 counter-streaming events, 6 with other CME
signatures, 3 over-expansion events. Data shown from February 28 and April 21 1994.
Identified with SXT events, Feb. 20 and April 14, 1994. Events "obviously associated"
with CIR shocks were eliminated. Simlution results again (see Goetal:94a).
Why dosen't the expansion start inside the critical piont with the reverse wave
running back into the Sun, so only a forward shock is seen? Easiest to explain if
the initial bulk speeds are high.
*Hanaoka et al., Simultaneous Observations of a Prominence Eruption Followed
by a Coronal Arcade Formation in Radio, Soft X-ray and Ha , 1994,
[Hketal:94]. RNR
KW: Eruptive Filament, Arcade Formation, Radio, Soft X-ray.
A detailed analysis of a filament eruption over the limb and the arcade
formation that took place afterwards. Good SXT, Ha, and radio observations.
Filament trace roughly co-spatial with radio and Ha signatures. Arcade formation
in relation to filament height given.
*Hiei, Structure and Development of Quiet Loops in the Solar
Corona, 1994, [He:94].
KW: Solar Corona, Quiet Loops, Dynamic Arcades.
A general summary of the evolution of coronal loops. Parameters given
for all classes of loops, then focus placed on quiet sun loops. Steady
loops in all locations and loop-loop interactions in ARs all show a slow
time evolutionary time scale (order 1000 Alfven times). Suggest processes
other than reconnection. Lab rates (~30 Alfven times) agree with flare
loops and transient brightenings. Discriptions of arcade evolution given.
Mention of the Jan. 16, 1993 event as showing widening prior to the arcade
appearence. Discussion of the shrinking loops of the Jan. 24, 1992 CME.
A plot of the ejecta and arcade loops on a time/height grid. Successive
loops are larger (20 km/s), but individual loops shrink (30 km/s). This
is seen in H alpha and soft x-rays. Loop tops about 4 MK, legs 2-3 MK.
*Hundhausen, Burkpile, and St. Cyr, Speeds of Coronal Mass Ejections: SMM
Observations from 1980 and 1984-1989, 1994, [HuBuCy:94]. RNR
KW: CMEs, SMM, Properties.
The mass and velocity SMM paper.
*Litvinenko and Somov, Magnetic Reconnection in the Temperature Minimum
Region and Prominence Formation, 1994, [LtSo:94].
KW: Reconnection, Prominence Formation.
A nice order of magnitude study of the reconnection parameters in the lower
solar atmosphere. Calculations done for the photosphere, temperature minimum, and
the chromosphere show that reconnection is favored in a thin layer (up to several
100 km thick) at the temperature minimum. Below this the plasma is too high; this
causes a low Alfven speed and the magnetic field does not contribute to the
dymanics. Above this the temperature is too high; this causes a high conductivity
and the magnetic diffusion into the current sheet is too slow. A field component
along the current sheet does not significantly affect the calculations. In the
temperature minimum the plasma is well coupled to the neutrals.
Calculations of mass flow up into the corona give rates consistent with
filament formation; 10^6 g in 10^4 s.
Martin, Bilimoria, and Tracadas, Magnetic Field Configurations Basic to
Filament Channels and Filaments<\it>, 1994, [MrBiTc:94].
KW: Filaments, Filament Channels, Chirality, Barbs, Properties, Hemispheric
Pattern.
The chirality (dextral and sinistral) of filaments and channels is defined
based on the rotation of the longitudinal magnetic field across the channel. The
definition of channels is reviewed, along with their priority to filaments, and
the determination of the axial field component from the plagettes and the global
field. The field below the filament spine, nearly horizontal. Examination of over
150 channels: plagettes anti-parallel across the channel, orientation becoming
less parallel and more verticle with distance from the inversion line. From this
develop model of rotational field.
Asymmetries of real channels, due to field variation of field density along a
channel and asymmetric width on either side of a channel. Patterns are best seen
in region of medium field density, corresponds to medium scale arcades (not AR and
not polar crown). Actual rotation is hard to observe in high density (too compact)
and low density regions (not well defined). Evidence for a continuum. Cases of
asymmetry across the inversion line more common in weak field. Evidence of a
tilted structure. Tilt towards the weak field side.
Often channels are only partially filled with filaments, or not at all.
Definition of sinsitral and dextral given, orientation of axial field relateive to
observer on the positive field side of the inversion line. The dominent filament
field is axial, ala Leroy. Filaments also are sinistral or dextral. Based on barbs
we have right and left bearing filaments.
Three data sets discussed: May 1989-July 1990, mostly AR; Sept 1991, whole
disk; 8-28 June 1992, whole disk. The first set included 82, the latter two 72,
plus paritaly and fully empty channels. Extensive records of relevant properties
recorded.
Initial results from 89-90 (??): Statistics heavily weighted to AR and
related filaments, mixed results by hemisphere. High latitude filaments appear more
likely to follow the pattern. Discussion of relation to the Rust-Leroy observations.
Chirality unchanged with cycle. Posit possible selection effect.
No correlation in the border filaments with larger magnetic context, ie
leading/trailing polarities. Also no evidence for chirality to relate to
asymmetries of field strength across the channel.
Results in later data sets: Comparison of the channel orientation and the
filament structure done. 25% hard-impossible to classify. For the other 75% a
1-1 correspondance was found. For quiesents, the hemispheric pattern found to
be statistical. Active region and border filaments are mixed, though some indication
that high latitude border filaments also show the pattern.
Channels observed without filaments, also eruption tends not to destroy the
channel, therefore, channel more important. Channels only connect to like
orientation channels. All filaments along a channel have same orientation. In ARs
some channels competely filled, others not. In QS most channels partially filled.
In general width of filament proportional to channel width.
Ends of filaments often high in the corona and off to one side of the channel.
Feet of barbs not rooted plagettes or network. Not true for ends. Note that the
field orientation should be inverse in the filament relative to the arcade.
Compares with Leroy's results. Discussion of measurement error due to orientation
of filaments at the limb.
The dominent hemispheric orientation aligns the axial fields of north-south
filaments with the global dipole.
Martin and Echols, An Observational and Conceptual Model of the Magnetic
Field of a Filament<\it>, 1994, [MrEc:94]. RNR
KW: Filaments, Structure, Barbs.
The main presentation of Martin's empirial filament model based on the May,
1992 filament and detailed magnetogram observations.
Pizzo, Global, Quasi-Steady Dynamics of the Distant Solar Wind 2.
Deformation of the Heliospheric Current Sheet<\it>, 1994, [Pz:94]. NR
KW: Solar Wind, CIRs, Simulations.
Modeling of CIRs out to 30 AU. Various dipole tilts are used.
1995
*Eselevich, New Results on the Site of Coronal Mass Ejections,
1995, [Es:95].
KW: CMEs, Global Coronal Structure, Streamers.
Using the SMM CME data base, CMEs were plotted on synoptic maps for 1985-
1989. Defines main streamer belt and branch streamers (called `streamers
without a neutral line'). At minimum all CMEs are on the main belt, close
to the equator. As the new cycle picks up (oct-nov, 1987) branch belts
appear, the CME count jumps by a factor of 2, and 17% of the CMEs are on
the branches. A few are not on any belt. Coronal hole number still limited,
and no major polar hole extensions. As activity picks up further (sep-oct,
1988) the main NL swings near the polar holes, there are more coronal holes,
and more branch belts. The majority (66%) of the CMEs are now on the branches,
and the bulk seem associated with the polar crown gap in longitude. Near max
the branch fraction rises to 80%. It is suggested that CME generation is
linked to the changing streamer belts and coronal hole structure.
Seperation from the closest NL plotted. Two periods defined: Jan. 1985
through Dec. 1987; and October 1988 through July 1989. In the first 88%
of associated streamers were associated with the main belt, in the latter
only 41%. Association criterion unclear (< d/2, what is d). The CMEs are
bunched near the NLs (more than 2/3s within .25 d), and appear symetrically
about them. Conclude that the streamers are the sites of the CMEs.
Note: need to check the papers which define how they map the neutral
lines, as I suspect that it is less direct than the ML synoptic maps.
*Feynman and Martin, The Initiation of Coronal Mass Ejections by Newly
Emerging Magnetic Flux<\it>, 1995, [FyMr:95]. RNR
KW: Filmament Eruptions, CMEs, Emerging Flux.
A statistical study of the relationship of emerging flux to filament eruptions
and CMEs. Association found in 2/3 of the cases studied.
*Gosling et al., A CME-driven Solar Wind Disturbance Observed at both Low
and High Heliographic Latitudes<\it>, 1995, [Goetal:95a].
KW: ICME, Storm, Properties, Solar Wind, Shocks, Ulysses, IMP8.
A discussion of IMP-8 and Ulysses data for a CME seen on February 21-22 and
26-28, 1994, respectively. Associated with an M4 flare at N09W02 on Feb. 20, 1994.
This was an LDE with type II and IV radio, and energetic protons peaking ~30 hrs
after the peak of the flare. These protons started shortly after the flare started.
The shock speed at Earth and IMP-8 was 800 km/s, with CME speeds to 1000 km/sec.
The CME leading edge speed as average transit speed was 992 km/s and initial launch
speed of over 1000 km/s, a very fast CME. Bz at Earth up to 40 nT. There was an 11
hour lag from the leading edge to the main CME passage.
Forward reverse shocks seen at Ulysses. Uses the same 1D model to suggest that
different responses at low and high latitudes are to the same initial CME. Cases
run for enhanced pressure, enhanced speed, and a combination. Implies over-pressure
more significant at high latitudes. Ulysses was at S54.3 W11.4, and 3.53 AU.
*Hammond et al., Latitudinal Structure of a Coronal Mass Ejection Inferred
from Ulysses and Geotail Observations, 1995, [Hametal:95].
KW: ICME, Shearing, Ulysses, Geotail.
Presentation of obeservations of a CME by both Ulysses and Geotail. This was seen
at Geotail (150 Re downtail) on Dec. 27, 1992, and by Ulysses (S20W51, 5AU) on
Jan. 10, 1993. Much of the paper deals with the technical aspects of making the
identification. Discussion of the expansion seen by Ulysses, but lacking at Geotail,
and of the shearing implied by the very different average speeds. Note is also made
of the latitudinal extent of the CME, for which this is the first observation.
*Kurokawa et al., Observations of Solar H$\alpha$ Filament Disappearances
with a New Flare-Monitoring-Telescope at Hida Observatory, 1995, [Kuetal:95]. NR
KW: Eruptive Filaments, Instrumental.
Instrumental overview and example eruptive events, including Nov. 5, 1992.
*Mouradian, Soru-Escaut and Pojoga, On the Two Classes of Filament-Prominence
Disappearance and Their Relation to Coronal Mass Ejections, 1995, [MoSEPj:95].
KW: Filaments, CMEs, Drivers.
Pushing the concept of thermal DBs in addition to eruptive DBs. Some useful
references to work on filament eruptions; Rompolt (symmetrical and asymmetrical
DBs), always asymmetrical in late phase; Vrsnak, unwinding prominence structure.
In general DB one leg lifts and all the material piles up in the other. In the
early phase both type rise at same rate. All filaments that fade in place are
taken as thermal DBs, can they be missing the draining seen in the semi-eruptives.
Complete lack of attention to the Shibata hypothesis, that filaments can simply
disrupt in place, allowing the plasma to drain, of Martin's point that sometimes
the flow is simply turned off. They believe the initial rise is driven by thermal
pressure?? And that DBs drive CMEs???
There is a discussion of H alpha contrast on-disk and above-the-limb.
*Tsurutani et al., Interplanetary Origin of Geomagnetic Activty in the
Declining Phase of the Solar Cycle, 1995, [Tretal:95].
KW: Solar Wind, Storms, Associations, Corotating Streams, HCS, CIRs.
An examination of the association of various solar wind structures with
geomagnetic activity in the declining phase of solar cycle 20 (1973-75). Focus
on the corotating high-speed streams from low latitude extensions of polar
coronal holes. Discount transients. Three largest storms are CMEs on top of
sector boundaries. Focus on 1974; two sector structure and for first 9 months
a strong pair of high-speed streams and recurrent activity. Typical stream
profile is rapid rise and long decay (max speed ~800 km/s), but there are
also "multiple onset" streams. Most of the large field magnitudes (> 15nT)
are near the leading edge of streams. Four largest fields associated with
CMEs (> 30 nT). Classify storms; 3 major (< -100 nT), 4 medium ( -70 to -85
nT), and the rest (> -70 nT). 12 of 18 stream entrances > -50 nT, some very
small, but peak speed gradient (?) and peak magnetic field similar to the
3 cases with Dst < -70 nT.
The two recurrent streams: 1, is negative (toward) polarity, southern
hemisphere; 2, is positive (away) polarity, northern hemisphere. 1 is more
effective early in the year, 2 becomes stronger in mid year and later. The
peak speeds go from 800-600 km/s and 625-825 km/s respectively. [This is
consistent with B angle (Russell-McPherron) effects.] These "storms" have
long recoveries [prolonged excitation??].
There are positive Dst periods associated with the inhanced ram pressure
(density) in slow speed streams. The high pressure regions tend to lead the
high field regions.
Long recovery periods show close correlation of Dst and AE indices,
ring current and substorms. These are termed "high-intensity long-duration
continuous AE activity" events, and are believed to be the result of Alfven
waves in the corotating streams (Tsurutani and Gonzalez, 1987). During these
periods high correlation of By and By with zero phase lag. This suggests
Alfven waves. Amplitudes largest in highest speed parts of the stream.
Periods of general quiet occur before HSS onset, over lapping with
positive Dst intervals. These periods have general low, steady, B and medium
to low declining velocities. They occur on the tail of previous high-speed
streams, with density rising towards sector crossing (HCS). High ram pressure
and lack of magnetic coupling produce positive Dst.
Distinquishes between storms (Dst) and sub-storm activity (AE).
Case examples given in detail. Slow speed, cool, high density streams
near the HCS. In ~20% of streams there are reverse shocks near the leading
edge (??) in which V increases, but B decreases, N is dead and T remains
the same. But no forward shock. Everything seems to be Alfven waves.
Apparent slight enhancement of negative sectors in March-April and
positive in September-October; ie Russell-McPherron. [Would B angle tilt,
exposing one high-speed stream better than the other be the same or is it
a different effect?]
Discussion of the three major storms in detail. All three occur near
the HCS crossing and fall in the main stream sequences (or their extension)
in spite of protestations to the contrary. Attempts at association with
solar events difficult and confused.
No major storms due to CIRs. Although there are strong fields there is
no prolonged Bs. High density tends to lead HCS, while high B trails slightly,
but leads the velocity rise into the high speed stream. This differs from
shock or cloud profiles.
1996
*Crooker et al., A Two-stream, Four-sector, Recurrance Pattern: Implications
from WIND for the 22-year Geomagnetic Activity Cycle, 1996, [Cretal:96]. RNR
KW: Solar Wind, Recurrance.
*Fox et al.Coronal Holes and the Polar Field Reversals,
1996, [FxMcIWl:96]
KW: Coronal Holes, Solar Cycle, Polar Reversal.
Description of the polar reversal of cycle 22. Question the lack of
consideration given to the sub-surface connections of coronal fields.
Cite Wilson and Giovannis (1994) comparisons of polar fields with flux
transport models, which have trouble matching the high latitudes. The
use of synoptic charts reviewed.
The polar crown, and its gap, which closes just prior to reversal.
Polar plots for CR 1815 to 1850 given. General tendancies: polar holes
tend to touch the pole at one edge; polar hole apparent rotation is
faster than expected. The reversal: a) polar hole with opposite polarity
hole at 45-50o (rise phase); b) polar hole extension to 45o, through the
gap and 180o around from the opposite polarity hole; c) polar hole
closes, but polarity remains attatched to the extention hole; d) polar
polarity becomes isolated and extension hole moves equatorward, closing
of the polar crown gap; e) Second new cycle hole forms, replaces the
first one, and rises towards the pole, as the new cycle polarity
encircles the old polar fields; f) Old polarity disappears, new cycle
hole reaches the pole; g) New hole consolidates, non-symetrically,
fills to 70o.
Same phases seen for the south polar reversal, and for both cycle
21 reversals. Phases checked against Mt. Wilson magnetograms. The new
cycle holes may have shared a common origin. Before the move to the
pole by one of them, a weak quadrapolar structure is seen. Refers to
super-regions, coming when high latitude holes move equatorward, where
they have a relatively slower rotation rate.
Argues that coronal holes are not random surface features, but are
part of the global dipole field and are generated below the solar
surface. Suggest the sub-surface fields are quadrapolar in nature. The
axes change during reversal and the hemispheres are independent till
after the reversals are complete. Suggest super-region location impies
a connection of toroidal and poloidal field generation. Claims alpha-
omega models can give low latitude toroidal fields but not the global
poloidal fields.
Key point? Evolution of the old polarity *away* from the pole
is hard to do with flux transport.