Accession Number:

ADA278672

Title:

The Relativistic Solar Proton Event of 11 June 1991

Descriptive Note:

Journal article

Corporate Author:

PHILLIPS LAB HANSCOM AFB MA

Personal Author(s):

• Smart, D. F.
• Shea, M. A.
• Gentile, L. C.

Report Date:

1993-01-01

Pagination or Media Count:

5.0

Abstract:

The X1238 solar flare that occurred at heliographic coordinates N31, Wl7 in NOAA region 6659 on 11 June 1991 commencing at 01 56 UT was the source of a number of energetic phenomena including intense X-ray and gamma ray emission and the acceleration of ions to relativistic energies. The small associated ground-level enhancement GLE of about 6 hours duration was mildly anisotropic even though a geomagnetic storm was in progress. The relative increases at sea level atmospheric pressure ranged between approximately 3 and approximately 7 at high latitude neutron monitors. The largest increases were observed by neutron monitors with an asymptotic cone of acceptance viewing into the probable IMF direction. We find a differential rigidity spectrum with a slope of -5.5 provides a satisfactory fit to the observed neutron monitor increases at the GLE maximum.

Descriptors:

• *SOLAR FLARES
• *COSMIC RAYS
• GROUND LEVEL
• EMISSION
• GEOMAGNETISM
• IONS
• REPRINTS
• SPACECRAFT
• ACCELERATION
• X RAYS
• PROTONS
• SPECTRA
• COORDINATES
• PRESSURE
• STORMS
• GAMMA RAYS
• MONITORS
• OCEANS
• BAROMETRIC PRESSURE
• ATMOSPHERICS
• NEUTRON DETECTORS
• SEA LEVEL
• MAGNETIC STORMS

Subject Categories:

• Astrophysics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE