The AMIE procedure is used to infer the electric potential, conductivity and currents in the northern hemisphere during the geomagnetic storm which occurred March 20 through 21, 1990.

Imagery - still images and animations - generated from the output of the AMIE procedure shows interesting ionospheric features. The animation sequences show Hall Conductivity with Height Integrated Current, Electric Potential , and Joule Heating prior to, during and after sudden storm commencement

Contents:

The Pre-storm period, March 20, 1990

The onset of the storm event...

The Post-storm period, March 21, 1990

Acknowledgements

Pre-Storm Sudden Commencement (Pre SSC)

Equivalent Current and Hall Conductance

Electric Potential

Joule Heating

Storm Sudden Commencement (SSC)

Post-Storm Sudden Commencement (Post SSC)

Equivalent Current and Hall Conductance

Electric Potential

Joule Heating

• 00:00 - 06:10 UT Frequent Bz polarity changes with IMF tangential components of magnitude less than 8 nT, average equivalent current values of 400 kAmp, and small expansions and contractions of the auroral oval seen in the Hall conductance.(1 Mb)

• 06:15 - 10:00 UT Average equivalent current values of 300 kAmp with quiet, contracted auroral oval seen in Hall conductance patterns. (531 Kb)

• 10:00 - 11:00 UT Equivalent current peaks of ~600 kAmp with apparent southward IMF turning followed by decay as IMF turns northward, auroral oval expansion and parital contraction.(200 Kb)

• 11:05 - 13:00 UT Average equivalent current values of ~400 kAmp inferred polar cap expansion and auroral oval expansion after 1200 UT.(367 Kb)

• 13:00 - 21:15 UT Average equivalent current values of 700 kAmp and active auroral oval.(1.5 Mb)

• 21:20 - 22:45 UT Average equivalent current values of 300 kAmp and quiet, contracted auroral oval.(283 Kb)

00:00 - 06:10 UT, Rapid IMF Bz Oscillations

• 00:00 - 00:20 UT Normal 2 cell convection pattern, dayside and nightside reconnection in balance.(96 Kb)

• 00:25 - 00:50 UT Convection retreats to nightside.(99 Kb)

• 00:55 - 01:35 UT Dayside reconnection begins, inferred polar cap expansion.(138 Kb)

• 01:35 - 1:55 UT Small geosynchronous particle injection, dayside convection decays followed by enhancement.(93 Kb)

• 02:00 - 02:40 UT Inferred polar cap expansion.(142 Kb)

• 02:40 - 4:20 UT Distorted 2 cell convection influenced by large negative By component of IMF.(307 Kb)

• 04:20 - 5:15 UT Weak convection pattern.(173 Kb)

• 05:20 - 06:10 UT Normal 2 cell convection pattern, convection retreats to nightside.(154 Kb)

  06:15 - 10:30 UT, IMF Data Gap

• 06:15 - 08:30 UT Weak convection signatures interspersed with normal 2 cell convection followed by dominate nightside convection. (326 Kb)

• 08:35 - 9:20 UT Dayside reconnection begins, dayside convection enhances, inferred polar cap expansion.(128 Kb)

• 08:40 -10:10 UT Dayside convection enhances, polar cap expansion begins, nightside reconnection begins, small geosynchronous particle injection event followed by normal two cell convection.(264 Kb)

• 10:15 - 11:10 UT Strong 2 cell convection, rapid nightside variations allowed by decay of dayside convection and dominate nightside convection.(200 Kb)

  11:00 - 21:15 UT, Bz negative, By variable

• 11:15 - 12:50 UT Dayside convection begins, expanded two cell convection and geosynchronous particle injection event at ~12:30 UT followed by development of distorted dayside convection.(305 Kb)

• 12:55 - 17:00 UT Normal two cell convection, average cross polar cap voltage ~80 kV.(793 Kb)

• 17:00 - 18:05 UT Rapid nightside variations and geosynchonous particle injection event.(233 Kb)

• 18:10 - 19:00 UT Normal two cell convection, average cross polar cap voltage ~75 kV.(200 Kb)

• 19:05 - 19:55 UT Rapid nightside variations and geosynchonous particle injection event.(207 Kb)

  21:20 - 22:40 UT, Bz positive, Storm Sudden Commencement at 22:45 UT

• 20:00 - 21:15 UT Strong two cell convection, peak cross polar cap voltage~100 kV, followed with decay of dayside convection.(237 Kb)

• 21:20 - 22:30 UT Convection retreats to nightside.(229 Kb)

• 22:35 - 23:45 UT Storm Sudden Commencement.(326 Kb)

• 00:00 - 04:15 UT Bz predominantly negative with brief positive excursions, globally integrated Joule heating average value ~125 GW.(318 Kb)

• 04:20 - 09:30 UT Bz predominantly positive, few brief negative excursions, globally integrated Joule heating average value ~75 GW.(355 Kb)

• 09:30 - 11:00 UT Probable Bz negative, globally integrated Joule heating average value ~75 GW.(134 Kb)

• 11:00 - 13:00 UT Bz negative, globally integrated Joule heating average value ~100 GW.(169 Kb)

• 13:00 - 21:00 UT Bz negative, globally integrated Joule heating average value ~100 GW.(644 Kb)

• 21:00 - 22:45 UT Bz positive, globally integrated Joule heating average value ~50 GW.(139 Kb)

• 22:50 - 0:200 UT Bz negative, SSC, high speed flow, globally integrated Joule heating average value ~500 GW, with peak value of ~600 GW.(334 Kb)

• 22:45 - 23:05 UT Rapid southward turning of IMF, current system response to SSC begins.(127 Kb)

• 23:10 - 01:00 UT Equivalent current peaks of ~1500 kAmp after SSC with significant auroral oval expansion. IMF Bz component is negative with high speed solar wind flow.(562 Kb)

• 01:05 - 10:40 UT Average equivalent current values of 700 kAmp, active auroral oval; repetitive enhancements and decays of dayside and nightside current systems.(2.2 Mb)

• 10:45 - 13:10 UT Average equivalent current now at 400 kAmp, dayside current system active, and auroral oval contracts.(485 Kb)

• 13:15 - 15:55 UT Peak equivalent current of ~1400 kAmp with average of 800 kAmp and auroral oval expansion.(607 Kb)

• 15:55 - 23:55 UT Auroral oval continues expansion with average equivalent current values of 700 kAmp.(1.7 Mb)

• 02:15 - 10:35 UT Vigorous 2-cell convection with an average cross polar cap voltage of ~100 kV. Continous nightside disturbances. Multiple geosynchronous particle injection events.(2.1 Mb)

• 10:45 - 10:50 UT Highly structured convection followed by development of distorted 2-cell convection.(80 Kb)

• 11:00 - 13:15 UT IMF data gap ends. Extreme distortion of dayside convection develops, Nightside convection dominates. Cross polar cap voltages decay to ~50 kV.(426 Kb)

• 13:25 - 14:15 UT Distorted convection gives way to development of more normal 2-cell convection. Inferred polar cap expansion begins.(214 Kb)

• 14:25 - 15:50 UTModerately disturbed two cell pattern.(393 Kb)

• 15:55 - 17:10 UT Nightside disturbances begin. Large particle injection event is followed by continuing nightside disturbances. By polarity changes twice followed by normal 2-cell convection. (308 kB)

• 17:15 -18:05 UT Nightside disturbances begin. Geosynchronous particle injection event. (221 Kb)

• 18:15 - 23:55 UT Repetitive periods of normal 2-cell convection events. (1.3 Mb)

• 02:00 - 10:45 UT Bz predominantly negative, high speed flow, repetitive enhancements and reductions, globally integrated Joule heating average value ~200 GW.(783 Kb)

• 10:45 - 13:30 UT Bz predominantly positive, globally integrated Joule heating average value ~50 GW.(225 Kb)

• 13:30 - 16:00 UT Bz predominantly negative, By polarity changing, globally integrated Joule heating average value ~400 GW.(245 Kb)

• 16:00 - 23:55 UT Bz negative, globally integrated Joule heating average value ~200 GW.(701 Kb)

W F Denig and F J Rich, Phillips Laboratory
O de la Beaujardiere, SRI International
J M Ruohoniemi, APL
E Friis-Christensen, Danish Meteorological Institute
J C Foster, Haystack Observatory
T Hughes, NRC Canada
R P Lepping, Laboratory for Extraterrestrial Physics, NASA
C G Maclennan, AT&T Bell Laboratories, Murray Hill, NJ, USA
A McEwin, Bureau of Mineral Resources, Canberra, Australia
L Morris, National Geophysical Data Center, Boulder, CO, USA
R J Pellinen, Finnish Meteorological Institute, Helsinki, Finland
R J Morris and G. B. Burns, Australian Antarctic Division,


Kingston, Tasmania, Australia

V Papitashvili, University of Michigan, Ann Arbor, MI, USA
J L Scali, University of Massachusetts, Lowell, MA, USA
Schlick and J. Bitterly, Universitee Louis Pastuer, Strasbourg, France
J R Taylor, T K Yoeman and M Lester, University of Leicester,

Leicester, U. K.

O Troshichev, Arctic and Antarctic Res Inst, St. Petersburg, Russia
P Van Eyken, EISCAT Scientific Association, Ramfjordbotn, Norway
N Sato, Nat Inst of Polar Research, Tokyo, Japan
P Sutcliffe, Hermanus Magnetic Observatory, Hermanus, South Africa
L Tomlinson, Institute of Geological and Nuclear Science Ltd,

Christchurch, New Zeland