Intense fluxes of low-energy electrons at geomagnetic latitudes above 85/sup 0/

Journal Article · Fri Jun 01 00:00:00 EDT 1984 · J. Geophys. Res.; (United States)

DOI:https://doi.org/10.1029/JA089iA06p03883· OSTI ID:6590717

Hardy, D A

A systematic survey was performed to determine the frequency of occurrence of intense fluxes of electrons above the level of the polar rain at geomagnetic latitudes > or =85/sup 0/ and their relationship to the orientation of the interplanetary magnetic field, the density and velocity of the solar wind, and geomagnetic activity. These intense fluxes we identify as the ''polar showers'' and ''polar squalls'' reported by Winningham and Heikkila (1974). For the study, 452 orbits of data from the SSJ/3 sensor on the DMSP F2 satellite were used. The orbits selected satisfied the criteria that the satellite attained a geomagnetic latitude > or =85/sup 0/ during the orbit and that interplanetary magnetic field (IMF) and solar wind data were available both for the hour in which the satellite passed over the northern hemisphere and for the previous hour. The key result of the study is that in 50% of the cases studied an electron flux exceeding the level of the polar rain was found in both hemispheres at geomagnetic latitudes > or =85/sup 0/ and that such occurrences are dependent predominantly, if not exclusively, on the B/sub z/ component of the IMF being positive. Unlike visible polar cap arcs, a positive value of the IMF B/sub z/ component appears to be both a necessary and a sufficient condition for the occurrence of such fluxes above 85/sup 0/ geomagneticc latitude. Occurrence is independent of the IMF B/sub x/ and B/sub y/ components. The occurrence is strongly skewed toward Kp = 0, but an occurrence exceeding 30% is found up to a Kp = 4. The occurrence is independent of the number density or velocity of the solar wind.

• Research Organization: Air Force Geophysics Laboratory, Hanscom Air Force Base
• OSTI ID: 6590717
• Journal Information: J. Geophys. Res.; (United States), Vol. 89:A6
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
IONOSPHERE
ELECTRON PRECIPITATION
ENERGY DENSITY
INTERPLANETARY MAGNETIC FIELDS
POLAR CUSP
POLAR-CAP AURORAE
SOLAR WIND
AURORAE
CHARGED-PARTICLE PRECIPITATION
EARTH ATMOSPHERE
MAGNETIC FIELDS
PLANETARY IONOSPHERES
SOLAR ACTIVITY
640201* - Atmospheric Physics- Auroral
Ionospheric
& Magetospheric Phenomena