Overview of the solar and interplanetary phenomena leading to the major geomagnetic disturbance on 24 March 1991

Journal Article · Mon Jul 01 04:00:00 EDT 1996 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.51547· OSTI ID:451681

Shea, M A; Smart, D F ^[1]

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1. Geophysics Directorate/PL, Hanscom AFB, Bedford, Massachusetts (United States)

Solar activity associated with NOAA Region 6555 was unusually high during its transit across the solar disk in March 1991. A major and very impulsive solar flare with soft X-ray onset at 2242 UT occurred on 22 March. This 3B, X9.4 flare was accompanied by strong solar gamma ray emission and the type of radio emission often used as coronal mass ejection (CME) proxies. Approximately four hours later, a series of major flares gave rise to long duration X-ray emission but without the radio signatures used as CME indicators. Although these major solar events were similar to other activity this solar cycle, the combination of extremely powerful solar activity, a major solar particle event and rapidly moving interplanetary shocks combined to give one of the most intense geomagnetic storms of this solar cycle. There were two momentum impulses to the magnetosphere. The first at 0342 UT on 24 March is associated with the rapidly moving interplanetary shock. The second at 1920 UT is associated with the major increase in geomagnetic activity. The solar and interplanetary events that preceded the geomagnetic storm are discussed together with the effects of the storm on the cosmic ray intensity at the earth. Finally, using data from historical events such as those in July 1959 and November 1960, we speculate on the combination of solar and interplanetary circumstances that lead to increased radiation in the trapped radiation belts. {copyright} {ital 1996 American Institute of Physics.}

• OSTI ID: 451681
• Report Number(s): CONF-9408182--
• Journal Information: AIP Conference Proceedings, Journal Name: AIP Conference Proceedings Journal Issue: 1 Vol. 383; ISSN 0094-243X; ISSN APCPCS
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
COSMIC RAY FLUX
EARTH MAGNETOSPHERE
ELECTROMAGNETIC RADIATION
INTERPLANETARY SPACE
MAGNETIC STORMS
MAGNETOPAUSE
SHOCK WAVES
SOLAR ACTIVITY
SOLAR FLARES