What is the source of observed annual variations in plasmaspheric density?

Details What is the source of observed annual variations in plasmaspheric density? What is the source of observed annual variations in plasmaspheric density?

May 1995

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1995jgr...100.8013g&link_type=abstract

Journal of Geophysical Research (ISSN 0148-0227), vol. 100, no. A5, p. 8013-8020

Physics

7

Annual Variations, Plasma Density, Plasmasphere, Earth Ionosphere, Hydrodynamics, Oxygen Ions, Wind Effects

Scientific paper

Plasmaspheric densities have been observed previously to be higher in December than in June, with the ratio varying between 1.5 and 3.0 and with larger variations at lower L shells. In order to search for the cause of the observed annual variations, we have modeled plasmaspheric density, using a time-dependent hydrodynamic model. On an L = 2 field line with geomagnetic longitude equal to 300 deg, the modeled plasmaspheric densities were a factor of 1.5 times higher in December than in June. The modeled December to June density ratio was found to increase slightly with L shell, in contrast to observations; this discrepancy may be due to the fact that outer plasmaspheric flux tubes are never completely full. In addition, for an L = 2 field line with geomagnetic longitude equal to 120 deg, the modeled plasmaspheric density was higher in June than in December by a factor of about 1.2. Various numerical tests were also performed in order to examine the sensitivity of plasmaspheric density to various parameters. In particular, a large vertical neutral wind was applied in order to raise the O(+) profile which had the effect of raising plasmaspheric density by a factor of 6. This in conjunction with a theoretical analysis suggests that plasmaspheric density levels are very sensitive to O(+) levels in the upper ionosphere. We conclude that annual variations in plasmaspheric density are due to similar variations in ionospheric O(+).

Affiliated with

Also associated with

No associations

Rating

What is the source of observed annual variations in plasmaspheric density? does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with What is the source of observed annual variations in plasmaspheric density?, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and What is the source of observed annual variations in plasmaspheric density? will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1061335