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Substorm Analysis: Hot News

Substorm on 04/27-28 was imaged over Antarctica by DMSP F13
Perturbation in N-S convection observed by ESR (Eiscat Svalbard Radar)
Perturbation in N-S convection observed by Sondrestrom Radar is VERY SIMILAR to that seen at ESR.
Millstone Hill observed a rapid the plasma density decrease in the region of enhanced electric field.

Ikrutsk ISR observed changes in the plasma spectral parameters at the time of the substorm (.jpg version)

Substorm Observations 01 UT - 03 UT April 28, 1998

WLS operations at Millstone Hill observed the enhancement of sub-auroral latitude convection electric field and subsequent ionospheric heating and formation of a mid-latitude ionospheric trough during a moderate substorm observed between 01 UT and 03 UT on April 28, 1998.
Interplanetary magnetic field components observed on the ACE spacecraft indicate a southward turning of the Bz component preceeding 00 UT, followed by a sharp northward turning of Bz near 00:30 UT. Magnetic field response was sharp and prompt as seen in the onset of a negative bay in the European sector at Sodankyla and in the North American sector at Ft. Churchill.

Substorm development in the North American sector was recorded by the U Iowa POLAR VIS imager

Substorm development over Antarctica was recorded by DMSP F13 imager

The Millstone Hill radar observed an intensification of ionospheric convection at 60 deg Invariant latitude in conjunction with the substorm. Ion convection > 250 m/s (corresponding to electric fields > 12 mV/m) were observed in the NE-directed fixed position. Simultaneously, the plasma density decreased in the region of enhanced electric field and associated increase in the ion temperature due to frictional heating.

Elevation scans to the North of Millstone Hill during the substorm development 23:15UT; 00:40UT; 01:255UT; 02:105UT provide a cronology of the deepoening of the trough and its equatorward displacement.

The latitude variation of ionospheric parameters is determined by the Elevation scans to the north

Variation of electron density with latitude during 1st 24 hours of WLS98
Variation of ion temperature with latitude during 1st 24 hours of WLS98
Variation of electron temperature with latitude during 1st 24 hours of WLS98

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http://www.haystack.edu/~jcf/wls98/substorm.htm -- Revised: April 16, 1999.jcf@haystack.mit.edu