TY - JOUR

T1 - Superposed epoch analysis of high-speed-stream effects at geosynchronous orbit: Hot plasma, cold plasma, and the solar wind

AU - Denton, Michael H.

AU - Borovsky, Joseph E.

N1 - Copyright (2008) American Geophysical Union. Further reproduction or electronic distribution is not permitted

PY - 2008/7

Y1 - 2008/7

N2 - 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).

AB - 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).

KW - cir high speed streams DCS-publications-id

KW - art-923

KW - DCS-publications-credits

KW - iono-fa

KW - DCS-publications-personnel-id

KW - 123

UR - http://www.scopus.com/inward/record.url?scp=56749150624&partnerID=8YFLogxK

U2 - 10.1029/2007JA012998

DO - 10.1029/2007JA012998

M3 - Journal article

VL - 113

SP - 1

EP - 9

JO - Journal of Geophysical Research

JF - Journal of Geophysical Research

SN - 0148-0227

IS - A07216

ER -