Observations of effects from magnetospheric cusp movement during a solar proton event
The interplanetary magnetic field underwent a strong southward turning at the location of the ISEE 3 spacecraft, with B/sub z/ (in satellite coordinates) decreasing from +15..gamma.. to -15..gamma.. in the interval from 1540 UT to 1600 UT on August, 1979. Solar wind speed measurements at the spacecraft indicated that the southward turning of the IMF should have reached the front of the magnetosphere around 1625 UT. At that time the solar proton event of August 18, 1979, was still in progress. Observations from balloon-borne and ground-based instrumentation in Greenland in that period, around 1415 magnetic local time, showed an expansion of the polar cap, the cusp moving southward by at least 5/sup 0/ in latitude in 15 min, starting around 1635 UT. From changes in the energetic photon spectrum at ballon altitude, it is shown that the proton cutoff energy at Sondre Stromfjord, Greenland, prior to the cusp motion was in the range 6--10 MeV.
- Research Organization:
- Department of Physics, University of California, Berkeley, California 94720
- OSTI ID:
- 6019423
- Journal Information:
- J. Geophys. Res.; (United States), Vol. 86:A9
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
GENERAL PHYSICS
MAGNETOPAUSE
MAGNETIC FIELD CONFIGURATIONS
INTERPLANETARY MAGNETIC FIELDS
MAGNETOSPHERE
POLAR CUSP
SOLAR PROTONS
SOLAR WIND
BARYONS
EARTH ATMOSPHERE
ELEMENTARY PARTICLES
FERMIONS
HADRONS
MAGNETIC FIELDS
NUCLEONS
PROTONS
RADIATIONS
SOLAR ACTIVITY
SOLAR PARTICLES
SOLAR RADIATION
STELLAR RADIATION
640203* - Atmospheric Physics- Magnetospheric Phenomena- (-1987)