12,000

We have over 12,000 students, from over 100 countries, within one of the safest campuses in the UK

93%

93% of Lancaster students go into work or further study within six months of graduating

Home > Research > Publications & Outputs > Superposed epoch analysis of high-speed-stream ...
View graph of relations

« Back

Superposed epoch analysis of high-speed-stream effects at geosynchronous orbit: Hot plasma, cold plasma, and the solar wind

Research output: Contribution to journalJournal article

Published

Journal publication date07/2008
JournalJournal of Geophysical Research
Journal numberA07216
Volume113
Number of pages9
Pages1-9
Original languageEnglish

Abstract

Superposed epoch analyses of magnetospheric plasma analyzer (MPA) data from Los Alamos National Laboratory (LANL) satellites are performed to reveal the density, temperature and flow velocity behavior of the hot ion plasma (0.1–45 keV), the hot electron plasma (0.03–45 keV) and the cold ion plasma (1–100 eV) at geosynchronous orbit following the arrival of high speed solar wind streams at the dayside magnetopause. The analyses reveal three striking features. (1) The arrival of a high density solar wind plasma at the leading edge of a high speed solar wind stream induces a sharp enhancement in magnetospheric convection which leads to the delivery of a hot, dense “plug” of fresh plasma sheet ions and electrons to the inner magnetosphere. On average, this superdense plasma is observed at geosynchronous orbit for ∼20 h following convection onset. There follows an extended period when exceptionally hot plasma sheet ions and electrons of more usual density are continually convected to the inner magnetosphere - a environment that persists at geosynchronous orbit while the high speed stream prevails. (2) Flow velocities and convection speeds of eroded cold plasma moving toward the dayside magnetopause are calculated from MPA statistical analyses. Average convection speeds of 8–12 km s−1 are typical in plume material moving sunwards following the arrival of high speed solar wind streams at the magnetopause. (3) The density of plume material convecting to the dayside magnetopause during high speed streams which follow very calm periods (Kp ∼ 0) is around double that during high speed streams following periods when higher levels of convection persist (Kp ∼ 2).

Bibliographic note

Copyright (2008) American Geophysical Union. Further reproduction or electronic distribution is not permitted