Magnetosphere/Ionosphere
Event Study Goal
To follow a significant solar-terrestrial event from its origin at the Sun
and to trace the flow of particles and energy from the subsequent magnetic
storm through the dissipative elements of the magnetosphere, ionosphere
and thermosphere.
Solar Relations to Study
Identification and Timing of Solar Drivers
at the Leading Edge of the Storm
GEM Focus Area
Global Energy Flow Analysis Through Magnetic Storms:
How do energy and particles flow from the solar wind into and through the Magnetosphere and distribute themselves in various dissipation elements of the magnetosphere, ionosphere and neutral atmosphere?
General Magnetospheric Relations to Study and Understand
- Solar Wind Drivers--Initial and Main Phase of Storm
- Onset and Decline of Main Phase
- Modes of Recovery
- Role of Field Aligned Currents in Energy Transfer Process
Convection-Ring Current Decay
Substorm-Dst relations
- Relative Contributions of Convection and Charge Exchange
Specific Magnetospheric Relations for This Study
- ULF Wave Activity and Storm Timing
a. Do ULF waves play a role in particle accelerations
- Geosynchronous Energetic Particle Dynamics
a. Where do particles go when they are depleted?
b. How do populations get rebuilt?
- Variations in plasmaspheric drifts appear correlated to Kp
a. Is the causal or incidental?
- Variations in Energetic Electrons associated with particular coronal hole
a. What was unique in the solar terrestrial environment that generated
enhanced populations of 6.0- 7.8 MeV electrons during the recurrences of
this particular coronal hole
CEDAR Focus Areas
Identify Limitations and Deficiencies in Observations and Models.
Explore new modeling and data assimilation methods.
Ionospheric Relations to Study, Understand and/or Validate:
- Global Description of Neutral Winds, Temperatures and Neutral Composition
- Global Description of Joule heating
- Dynamics of the Low Latitude Trough
- High and Mid Latitude Convection Dynamics Relating to Magnetosphere and
Thermosphere Changes
- Structuring of High Latitude Patches, Polar Cap Arcs and Scintillation
- Ionospheric Morphology as Sensed by Ground and Space-Based Tomography
- Plasmaspheric Morphology and Dynamics as they relate to Ionospheric
Variations
- Energy Transfer to the Mesosphere
- Model Validation
- Ionospheric Signatures of Substorm Onset
Major magnetic storm classification (-105 nT Dst)
Availability of solar wind at storm onset
Reported storm Ionospheric/Magnetospheric effects
Status as recurrent activity
Likely association with increased flux of relativistic electrons
Availability of magnetospheric data from satellites
Mid 1993-Mid 1994: Robust, recurrent geomagnetic storms
(Geomagnetic indices, geosynchronous satellites, SAMPEX satellite,
D. Baker 1995 GEM and CEDAR presentations)
Late 1993: Sector boundary structure began to reorganize (S.
Watari, 1995 IUGG presentation)
Early November 1993 storm was 4th recurrence out of 5 associated
with long-lived coronal hole and high speed recurrent stream (Aug-
Nov 93 Ap index, Aug-Dec Dst index, IMP-8 plasma data, Yohkoh soft
X-ray images, D. Knipp 1995 GEM,CEDAR, SIP and SOLTIP
presentations)
In each of 5 recurrences enhancements of 6.0-7.8 Mev
magnetospheric electrons observed by LANL geosynchronous
satellites. Similar enhancements were not seen in other high speed
streams during this interval (G. Reeves).
Yohkoh imagery clearly showed coronal hole from 30 Oct and
subsequent days (Yohkoh imagery, A. McAllister)
Mauna Loa K-Coronometer shows faint CME on east solar limb at
2000 - 2100 UT on 31 Oct (High Altitude Observatory NCAR, A.
Hundhausen). The impact of this ejection, if any, on the early
November 1993 storm remains to be determined.
An M-class flare associated with an active region near the coronal
hole was observed at 2230 UT on 1 Nov (Yohkoh Imagery and GOES-7
Xray observations) Impact, if any, on early November 1993 storm
remains to be determined.
Late 2 Nov-early 3 Nov:
- Kp index in 0 to 1- range,
- IMP-8 in duskside magnetosheath at ~-25 Re (A. Lazarus)
- GEOTAIL at duskside magnetosheath at ~-200 Re (M. Nakamura)
3 Nov, ~06 UT:
- Sudden increase in solar wind plasma density.Solar wind density increased sufficiently to allow IMP-8 to sense solar wind plasma characteristics. IMP-8 apparently remained in the magnetosheath.
(A. Lazarus)
- Solar wind velocity ~275 km/s
- Cross polar cap voltages ~ 30 kV (M. Hairston)
3 Nov, ~07 UT:
- Large anisotropy in ring current ions developed,
- Smaller anisotropy in plasma sheet electrons (G. Hoogeveen and
LANL MPA team)
- Dst positive phase begins
3 Nov, 17 UT-19 UT
- ~1720 UT Sudden Commencement (SC)
- Sparse IMP-8 data indicates velocity jump and density
enhancement, but small magnetic field components at SC (A.
Lazarus, R. Lepping)
- ~1800 UT Plasmasphere disappeared from nightside
geosynchronous satellites but remained on dayside (G.
Hoogeveen and LANL MPA team)
- Dst began to decline
- Polar Cap Index began to rise
- Ground magnetic observatories and polar satellites record
small to moderate responses (D. Knipp, data gathered for
assimilation)
- Southern hemisphere riometer absorption event observed (T.
Rosenberg)
- ~ 1830 UT GEOTAIL observed sudden jump in magnetic field intensity,
associated with shock arrival. Solar wind speeds measured in the
magnetosheath increased from 300 km/s to 350 km/s
(M. Nakamura)
3 Nov, 20 UT-21 UT
- IMF northward, ionosphere and ground activity quiet (D. Knipp,
data gathered for assimilation)
3 Nov 21 UT - 22 UT
- IMF turns moderately southward (-5 nT),
SuperDARN radars observe clear duskside response (K. Baker
and M Ruohoniemi)
- Ionosphere and ground activity enhancements begin (D. Knipp,
data gathered for assimilation)
3 Nov 22 UT- 23 UT
- IMF strongly southward (-15 nT) ionosphere and ground
disturbances continue (D. Knipp, data gathered for
assimilation)
3 Nov 23 UT -24 UT
- Possible magnetic flux rope passage (N. Crooker, J. Foster)
IMF northward-southward-northward, southward magnitudea ~
35 nT
- Other components also changing polarity
Hour long extreme density enhancement (> 75/cc at peak)
Thermal speed decreased with density enhancement
- 500-800 nT magnetic bays near local midnight (H. Leuhr, IMAGE
data and C. Szuberla, Lonyearyben data)
- 300-500 nT bays beyond midnight (G. Rostoker, CANOPUS, J.
Hughes MACCS, E. Friis-Christensen, Greenland data)
LI>Millstone Hill Radar recorded prompt onset of precipitation
produced ionization at lower F-region heights near L=4 in
evening sector and at L=3.5 a deep ionization trough (J. Foster)
- Beginning of more than 12-hour complete depletion of SAMPEX
observed energetic electrons (>3.0 MeV) at 3 < L < 8 (X. Li)
4 Nov 00 UT-01 UT
- Millstone Hill observed ionospheric F-region uplift indicating
deep penetration of disturbance electric fields to low
latitudes (L < 2) (
J. Foster)
- LANL geosynchronous satellites near local noon encountered
magnetosheath for short time, indicating magnetopause was
inside geosynchronous orbit (J. Borovsky,
G. hoogeveen, and LANL MPA team)
- IMP-8 observes solar plasma flow angle suddenly shift to
come from west of sun (
A. Lazarus)
- ~01 UT IMP-8 observes continuous southward field of -25 nT
until rapid entry into magnetosphere at ~ 01 UT
4 Nov 01 UT -22 UT
- Kp maximized at 6-
- Ap maximized at 78
- Dst minimized at -105 nT
- IMP-8 in magnetosphere, other data gives strong credence to
ongoing southward IMF conditions and high speed flow
- Antisunward convecting F region patches (D. McEwen)
- Antisunward flow observed by DMSP satellites (M.
Hairston)
- Ongoing nightside magnetic bays (ground mag
observatories)
- ULF wave activity in morning sector, possibly associated
with development increased flux of relativistic electrons at Geosynchronous orbit(G. Rostoker)
- Positive phase ionospheric storm begins **NOTE this is
different than positive phase DST,** Southern hemisphere
ionosondes see storm progress equatorward. Ionosonde data
lost from Mawson and MacQuarie Island due to strong
absorption (P. Wilkinson)
- ~0515 GEOTAIL observed a solar wind speed increase to a maximum
of 700 km/s. The speed remained at the at level for the rest of the
day.(M. Nakamura
)
4 Nov
- 00 UT -12 UT Strong, stable nightside field-aligned current
structures sensed by FREJA satellite (J. Gary and L. Zanetti )
- ~22 UT Extreme, but short lived disturbance at nightside
ground and satellite locations. Source and characteristics of
disturbance remain to be determined (D. Knipp, assimilated
data)
- Preliminary AMIE results indicate cross-polar cap voltages in
excess of 160 kV (D. Knipp and B. Emery)
Early 5 Nov
- IMF apparently goes northward for a few hours.
Stable sun aligned arcs observed by Eureka MSP (D. McEwen)
- ~03 UT LANL geosynchronous satellites observed increase in
penetrating background due to energetic electrons (G.
Hoogeveen and LANL MPA team)
Dst recovery begins
5 Nov -7 Nov
- Geosynchronous penetrating background due to energetic
electrons peaked on 8 Nov (G. Hoogeveen and LANL MPA team)
- Ongoing ULF wave activity observed in CANOPUS array (G.
Rostoker)
- Well developed negative phase ionospheric storm in progress.
Storm affects ionosondes at Hobart, Canberra and Mundaring (P.
Wilkinson)
- 7 Nov Intermittent IMP-8 data suggest solar wind speeds in
excess of 600 km/s ( A. Lazarus)
8 Nov
- IMP-8 emerges into dawnside solar wind, hourly average
velocities in excess of 600 km/s recorded
- Ionosondes see ionospheric Storm abate (P. Wilkinson)
11 Nov
- Dst recovered to prestorm values
- Polar Cap index declined to quiet
- Ap recovered to prestorm values
Original Concept For Study
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Last modified: September 6, 1995
.