Plasmaspheric storm time erosion

Details Plasmaspheric storm time erosion Plasmaspheric storm time erosion

Jun 2000

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2000jgr...10512997c&link_type=abstract

Journal of Geophysical Research, Volume 105, Issue A6, p. 12997-13008

Physics

15

Magnetospheric Physics: Magnetosphere/Ionosphere Interactions, Magnetospheric Physics: Plasmasphere, Magnetospheric Physics: Storms And Substorms

Scientific paper

Unusually low whistler mode group delay times are observed by VLF Doppler receivers at both Faraday, Antarctica, and Dunedin, New Zealand, following magnetic storms. These are typically caused by plasmaspheric electron concentration depletions near L=2.4 and not by changes in the VLF wave propagation path. Using a data set that is almost continuous since 1986, we find that depletions during storms in the solar minimum of 1995 are significantly deeper than in the minimum of 1986. Event studies at Faraday show that the electron concentration depletions caused by storms were about a factor of 2 in 1986 and a factor of 3-4 in 1995, independent of the time of year. However, the depletions observed by both sites are significantly deeper than those observed in 1958 and 1961 using natural whistlers (i.e., factors of 2-4 compared to 1.3). The Sheffield University Plasmasphere Ionosphere Model (SUPIM) has been used to investigate possible causes of the plasmaspheric electron concentration depletions observed in the whistler mode data. Thermospheric parameters, including a reduction in the concentration of neutral hydrogen and oxygen at all altitudes, were perturbed by a factor of 10 from their normal levels. However, the plasmaspheric depletions produced were only of the order of 10% after 27 hours. It is unlikely therefore that thermospheric modifications alone are responsible for the depletions observed in the data. Additionally, a tube of plasma was moved to higher L shell under the influence of an equatorial meridional E×B drift velocity of 1000 m s-1and showed levels of depletion of about a factor of 2. Although it is possible to generate plasmaspheric concentration depletions using the drifting tube model, the depletions are smaller than those observed and the outward E×B drift velocity needed is a factor of 2 greater than those reported previously at L=2.4. It is therefore unlikely that the tube drifting mechanism is the principal cause of the observed plasmaspheric electron concentration depletions at L=2.4. Although no mechanism is clearly identified in this study, the ground-based results presented in this paper indicate erosion levels of similar structure and magnitude to electron concentration profiles from the ISEE 1 satellite in the aftermath of magnetic disturbances during 1983, thus providing a long-term record of plasmaspheric erosion.

Affiliated with

Also associated with

No associations

Rating

Plasmaspheric storm time erosion 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 Plasmaspheric storm time erosion, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Plasmaspheric storm time erosion will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1350790