Electron density in the plasmasphere: whistler data on solar cycle, annual, and diurnal variations
Whistler data are used to present a statistical view of equatorial plasmaspheric electron density n/sub eq/ and associated tube electron content N/sub T/ (defined as the number of electrons in a geomagnetic flux tube of 1cm/sup 2/ crosssectional area at 1000km altitude and extending to the magnetic equator). The data were acquired between 1959 and 1973 at Byrd (Lapprox. =7), Eights (Lapprox. =4), and Siple (Lapprox. =4), Antarctica, which are within 1 hour of the same geomagnetic meridian, and from Stanford, California (Lapprox. =2). The plasmaspheric n/sub wq/ profile beyond Lapprox. =3 is dominated by variations associated with magnetic disturbances and sunsequent recovery. In the aftermath of disturbances the plasmasphere tends to be divided into an inner 'saturated' region, which is in equilibrium with the underlying ionosphere in a diurnal average sense, and an outer 'unsaturated' region, which is still filling with plasma from below. In the outer plasmasphere bond approx.3.5 R/sub E/, diurnal variations appear as relatively small effects superimposed on larger storm-associated variations. Large numbers of whistler traces (as many as 3000 in some cases) were scaled for each of several months. These data sets form the basis for approximations to n/sub eq/ profiles to form log/sub 10/ (n/sub eq/) =aL+b. These profiles are offered for reference use in estimating plasmasphere density levels. The previously reported annual and solar cycle variations are further documented by new evidence that these effects diminish with increasing L beyond Lapprox. =3.
- Research Organization:
- Radioscience Laboratory, Stanford University, Stanford, California 94305
- OSTI ID:
- 6694973
- Journal Information:
- J. Geophys. Res.; (United States), Journal Name: J. Geophys. Res.; (United States) Vol. 83:A7; ISSN JGREA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ANNUAL VARIATIONS
ATMOSPHERICS
DAILY VARIATIONS
ELECTROMAGNETIC RADIATION
ELECTRON DENSITY
EQUATOR
MAGNETIC STORMS
NOISE
PLASMASPHERE
RADIATIONS
RADIO NOISE
RADIOWAVE RADIATION
SOLAR CYCLE
VARIATIONS
WHISTLERS