Plasmasphere Magnetosphere Interactions (PMI) Focus Group Sessions, GEM 2010
Notes taken by J. Goldstein
• This document attempts to summarize main or outstanding points of most of the PMI presentations.
• It should not be considered a comprehensive or complete set of notes.
• Figures shown are taken from particular presentations and included here to clarify/augment textual notes. All
figures must be reproduced only with permission of the authors of the presentation.
OVERVIEW OF SESSIONS:
For notes from Breakout 5
held jointly with Radiation
Belts & Wave Modeling
(RBWM) Focus Group,
contact RBWM conveners.
Monday
21 June
.
.
PMI Breakout 1:
"EMIC"
10:30-12:15
Richard Denton
EMIC Simulations.
.
Cold plasma makes big difference to EMIC waves. Simulations of EMIC waves. Curvilinear coordinates (fieldaligned). Richard looks at the H and He surfaces. "Bi-ion resonance". PA scattering can move waves from one
surface to another. Fraser: what fraction of He used in these simulations? ANS: 14% He. High? Maybe OK.
Effect of O+ on wave propagation: Initial-val sims. Higher O+: waves less guided and more isotropic.
O+ Heating: Cold oxygen heated to keV temperatures. Heating efficiency decreases with temperature.
O+ Effect on Wave growth:
Plasmapause 14% He+, No O+: H waves grow in ptrough in agreement with
Anderson 1992. Add in O+: waves don't grow in the p'pause boundary! Hot/Cold & composition very important.
Fraser: measuring wave normal vector is nontrivial. Tperp/Tpara ~2, Beta_para~0.8.
Jennifer Posch
Relationship between EMIC waves & Plumes at geosynch.
.
Observational EMIC wave study.
Plumes: proposed source/cause of EMIC waves during storms. True?
To answer this, catalogued Pc1 EMIC waves from 1996-2003 at 3 Automated Geophysical Observatories (AGOs)
at auroral zone latitudes in Antarctica.
Compare these data with LANL MPA on 1990-095.
Plume occurrence:
determined for 2-hour intervals using MPA.
Criteria for plume occurrence: Cold ion density between 10 and 400 cm-3
Hot ion density < 3 cm-3
|velocity| > 12 km/s
Solar Wind Pressure: Seems most correlated with EMIC waves.
Plume Correlation?
Pc1 – Plume correlation is not very good. Occurrence: different vs. year.
MLT Distribution:
diurnal distributions are different. Pc1: peak ~14-15 MLT. Plumes: ~19 MLT. AGOs'
MLT distribution similar to that from AMPTE CCE [Anderson et al., 1992].
AGO
AMPTE CCE
Superposed Epoch Study:
bins: 1 day, 2 hours.
• 133 events with timing determined by McPherron and Weygand, [2006].
• SSCs: 232 events.
• HSS: 25 events [Denton and Borovsky, 2008].
Conclusion: very poor correlation of EMIC with plumes. Plasmasphere OK.
Causes of EMIC:
RC Pressure, Tperp/Tpara. High cold density lowers thresh for wave growth (linear
theory). Wave velocity also important (nonlinear treatment).
Liz MacDonald
EMIC Waves, Unstable Particles, & Precipitation.
.
Spasojevic & Fuselier [2009]: arc motion rel. to SW transient events. Detached arcs.
Separation when Bz goes northward.
Using proxies for EMIC wave growth Sigma, S. [Blum et al., 2009]. The proxies seem to agree with GOES actual
wave measurements.
Miyoshi, POES. Are there more systematic studies? AGO-80 Sandanger et al. Need plots of Sigma and S with
relative contributions of density and temperature anisotropy indicated.
Brian Fraser
EMIC Waves, geomagnetic storms, & plasma plumes.
A. Halford et al. study.
Ground-based
Pc1-2 EMIC waves... not seen during storm main phase. More in recovery phase.
Theory/Simulation
Significant occurence during main phase
CRRES
more likely during storm main phase.
1.
2.
3.
4.
EMIC 1.6 x more likely during storms.
Mean location of EMIC waves during storms: L=5.83, MLT= 15.38.
Majority 56.25% of storm-time EMIC occurred during main phase.
Recommend using occurrence rates (over simple counts). Storm phase definition very important!
.
PMI Breakout 2:
"Wave-Particle Interactions & IMEF"
13:30-15:00
Anatoly Streltsov
Whistler Propagation along density gradients.
.
Whistlers guided by p'pause. Irregularities guide whistler. Numerical results. e- MHD simulation.
• Electron momentum equation
• Maxwell's equations
• 2D field-aligned coord system: sim domain. Box model.
Periodic wave in a homogeneous plasma.
Localized wave in a homogeneous plasma.
Localized wave in a high-density duct.
Symmetrical Ducts: High density duct leaks energy.
But leakage is small or zero for particular perpendicular wavenumbers; i.e., when width of duct is equal to integer
number of smallest wavelengths. Whistlers can also be trapped in the region of a monotonic density gradient such
as the newly-formed plasmapause during geomagnetic storms.
JG: Can you have duct density vary along F.L.? Also, can you model multiple ducts?
Lunjin Chen
Instability of Magnetosonic Waves
.
Global distribution (proton rings) from RAM simulation? Preferential region of magnetosonic wave activity?
Unstable freq. band for MS waves.Ring Current
Atmospheric interaction Model (RAM) of
Jordanova [2010] simulate cold plasma density and
ring current proton PSD (500 ev – 400 keV) during
2001 April 21 storm.
Simulated energetic H+
phase space density (PSD) at L=5 during main
phase, vs. MLT. Bi-Maxwellian on dayside. Proton
ring formation due to energy-dependent drifting.
Instab favored when proton ring vel comparable to
(but nec. exceeding) Alfven speed.
Unstable frequency band: modulated/controlled by
the ratio of the Ring Velocity (vk) to the Alfven
velocity (vA).
Center freq of unstable magnetosonic waves, using
LOCAL growth rate calculation, with no
propagation effect taken into account
(not
included).
• MS waves at low freq, unstable in high density region.
• MS waves at high freq: unstable outside plasmasphere on dayside.
Vania Jordanova
Simulations of RC anisotropy in non-dipole fields.
.
Ring Current simulation using RAM. Jordanova et al. [1994, 2006].
• RC dynamics during 20-21 Nov 2002 storm. Double Dip: SymH -90 nT @20 UT, -127 nT @34 hrs.
• Mechanisms for P/A anisotropy.
• Assess effect of non-dipolar B-field geometry.
Magnetically Self-Consistent Model (RAM-SCB):
RAM: Bounce avg Boltzmann, all major loss proc. Empirical E-field. General B. Coupled to Psphere.
3D Equilibrium code [Cheng, 1995; Zaharia et al., 2004]: pressure balance, Euler potentials. Self-consistently
calculate 3D B-field in force balance with anisotropic plasma pressure from RAM.
Results with Weimer [2001] E-field.
Ring Current H+ Anisotropy
more field-aligned = green
red = pancake
EMIC Wave Growth
Include non-dipolar B:
B-field decrease.
Velocities increase.
(on the dusk-midnight side).
Lasse Clausen
Subauroral E-fields seen by mid-lat SuperDARN radars.
.
Incoherent scatter radar (ISR) SuperDARN
Measure drifts and infer E-fields.
Interested in Subauroral (penetration) E-field.
overshielding (Northward Drift)
vs
undershielding (southward drift)
SuperDARN:
The N-S velocity in the midlatitude ionosphere tracks the IMF Bz with a 15-minute delay.
Jay Albert
Some thoughts on Quasi-Linear Theory.
Very brief talk. Full version in Yuri's session. QLT: quasi-linear theory.
Chorus: coherent narrowband, can be very large amplitude.
2 mV/m
Li et al. [2007] CRRES
30 mV/m
Santolik [2003] Cluster
100 mV/m
Cully et al. [2008]
THEMIS
250 mV/m
Cattell et al. [2008]
STEREO
Seems like QLT shouldn't apply.
.
PMI Breakout 3:
"Plasmaspheric Dynamics & Plume Recirculation"
Rick Chappell
Cold Plasma dynamics in the afternoon drainage corridor.
15:30-17:00
.
Three levels of density outside the LCE:
Nightside:
Dayside:
Dusk:
no filling
filling
filling
0 cm-3.
0-10 cm-3
0-1 cm-3
Dusk, shorter time spent in filling zone
(dayside) so lower. Dayside flux tubes
benefit from traversal of entire dayside.
Dusk flux tubes zip by.
"Plasma Drainage Corridor" is region where
draining flux tubes—if there are any—go.
It is a convection region.
Fluctuating convection level can produce
constantly-changing levels of density,
sampling alternately from the "three
regions/levels of density" above.
•
•
•
Drainage corridor: plume shaped,
though the draining plasma may not be.
Within drainage corridor there is constantly changing variety of plasma characteristics. Plumes with 10s to
100s of cm-3. Dayside trough, dusk trough.
Mostly, on timescales of minutes, changing between the "three levels of density."
Singer:
ULF waves complicate the interpretation of the OGO-5 observation.
"sloshing" into & out of the detector.
The waves can produce
Mike Liemohn
Analyzing plasmaspheric dyncs from 90 storm simulations.
.
90 Storm simulations. All intense storms from 1996 – 2005. Different configurations to study dominant physical
processes. Processes: universal or driver-dependent?
HEIDI:
Hot Electron and Ion Drift Integrator. (origin: Michigan version of RAM.) Solves gyration- and bounce-averaged
kinetic equation [Fok et al, 1993; Jordanova et al., 1996; Liemohn et al., 1999, 2001, 2004].
HEIDI coupled to DGCPM [Ober, 1997]. Solve continuity equn for flux tube total content.
Hot plasma BC and E-field are things to change in matrix of solutions.
Dipole B, same grid res., for all sims. Only include H+ and O+ in RC.
E-Field:
BCs:
Volland-Stern (shielding, Kp driven)
Self-consistent (HEIDI-FAC driven)
LANL moments, no MLT dependence
LANL moments with MLT included via reanalysis
[O'Brien et al., 2007]
LANL reanalysis nightside average (no MLT dep)
23 October 1996
Plasmasphere (DGCPM) model compared to LANL MPA. Pretty good!
Plume Location Statistics
"Earliest and latest cold plume plasma" (> 3 cm3). 3-h Kp driven V-S E-field. Model agrees in
post-noon sector, but not morning. (Different
processes on morning and dusk sides.)
E-Field Models:
These results seem to show that both E-field
choices are pretty good.
Dennis Gallagher
Modeled Plume-to-magnetopause for 2000 Bastille Day storm.
.
Does dense plume plasma affect reconnection?
DGCPM in BATSRUS.
Plume to MHD density ratio only goes above unity when
magnetopause moves inward. Important at nominal mpause
location? This is a way to find out.
Mike Schulz
Mapping of Plasmaspheric Densities.
Plasma density N proportional to B2 along equatorial drift trajectory.
Schulz, M., Magnetosphere, in Handbook of the Solar-Terrestrial Environment, edited by Y. Kamide and A. C.-L.
Chian, ch. 7, pp. 155 −188, Springer, Heidelberg, 2007.
Pavel Ozhogin
Field-Aligned Density Asymmetry.
RPI field-aligned asymmetry. North-South Asymmetry.
Derive densities along field lines.
Higher Density in S. Hemisphere (Mar 2002)
March 2002:
Oct 2004:
Plasma moving from south to north.
Plasma moving from north to south.
Higher in N. Hemisphere (Oct 2004)
.
Jiannan Tu
Dynamic fluid-kinetic model of plasmaspheric dynamics.
Kinetic model with ionosphere self-consistently coupled.
Directly solve ion distribution functions [Singh et al., 1988; Khazanov et al., 1993; Liemohn et al., 1999].
Existing Full particle hybrid models:
No assumptions on ptcle distr. functions
Micro processes
Computationally expensive
Prescribed ionospheric boundary conditions.
New model:
Kinetic FLIP zone coupling
Multiple ion species: H+, O+, He+, electrons also can be included.
Applications: small scale sim. of refilling, dayside transport (plumes), and polar cap plasma outflow.
.
Tuesday
22 June
.
.
PMI Breakout 4:
"Closing the Loop on PMI" 10:30-12:15
Wen Li
Transport of suprathermal electrons as seen by THEMIS.
.
Electrons in the suprathermal energy range: 0.1 – 10 keV suprathermal e- are important to RB dyncs.
They control Landau damping of whistler-mode waves: Hiss (inside Psph), Chorus (outside).
Statistical distribution of suprathermal e- fluxes.
THEMIS A, D, and E [Angelopoulos, 2008]
June 2008 − Feb 2010
2.5 RE< R <10 RE
|MLAT| < 25°
24 MLTs
ESA for electrons
EFI for S/C potential (plasmasphere/ppause)
FGM background B-fields
Higher Energy
OUTSIDE PSPHERE
INSIDE PSPHERE
peak on nightside, e- flux decreases with MLT. lower than outside. peak at L~4, forming "ring"
Lower Energy
OUTSIDE PSPHERE
INSIDE PSPHERE
peak at 4-6 RE
decr with increasing L.
flux in the plasmaspheric plume region is extremely small during active times.
electrons trapped in the plasmasphere due to refilling.
Localized E-field & Energy-dependent azimuthal drifts.
Aron Dodger DGCPM & SW Modeling Framework.
Timing between PCP change and the subsequent plasmaspheric ressponse. Very preliminary results!
.
GROUP DISCUSSION
"Closing the Loop on Plasmasphere-Magnetosphere Interactions".
.
.
Talking points:
•
Plume: Is it a corridor or a thing? JG: It is a density feature that occupies the corridor.
•
Matching of crude models with what we see. In some senses these models do surprisingly well. But we still
have a long way to go. The models we have do a good job of indicating where the plume might be, but don't
really capture the structure inside it.
•
Howard Singer: How do we get the same level of general agreement to be attained by the global MHD
models? Multifluid? Grid resolution issues, and region 2 currents.
•
Filling of magnetosphere with particles from ionosphere: modeling of filling flux tubes.
•
Plumes: densest plasmaspheric features, but there's a "haze" of ionospheric-origin plasma.
•
Reiner Friedel: Can we incorporate ground-based measurements in PS modeling?
•
Is EMIC dependent on composition? Can we look at historical PS composition observations from S/C that
don't need pot. control?
•
PMI PRIORITIES:
(1)
Plasmasphere/Plume internal structure.
(2)
Get global MHD to capture plasmaspheric dynamics.
(3)
Modeling of filling flux tubes.
(4)
The EMIC Wave Challenge. Fraser/Denton. List events. Capture EMIC spatial distribution, wave
amplitude, background plasma composition & its effects, Alfven waves, mass density. Compare to
RBSP?
(5)
Future PMI Session on Ground Based Observations. Invite some speakers.