Open AccessGround and satellite observations of substorm onset arcs
Author(s) -
Shiokawa K.,
Yago K.,
Yumoto K.,
Baishev D. G.,
Solovyev S. I.,
Rich F. J.,
Mende S. B.
Publication year - 2005
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2005ja011281
Subject(s) - substorm , satellite , geology , geophysics , geodesy , remote sensing , magnetosphere , physics , astronomy , plasma , quantum mechanics
Auroral features and associated particles and fields are investigated for a sequence of substorm onsets observed at ∼1900 MLT on 24 October 2000. During a 30‐min interval at 1020–1050 UT, we identified three Pi 2 wave packets with positive H enhancements at midlatitudes and associated auroral brightenings in auroral images obtained by a ground all‐sky camera and the IMAGE FUV imager. The DMSP F15 satellite crossed brightening arcs during the third Pi 2 pulsation in the field‐of‐view of the ground camera at Tixie (66.0° MLAT), Russia. The crossing was 1–2 hours duskside of the main onset local time. The brightening arcs were located in the region 1 upward field‐aligned current system. The most equatorward arc, which brightened just after the second Pi 2 pulsation, was at the equatorward boundary of the region 1 current and in the sunward convection region. The arcs corresponded to inverted‐V accelerated electrons with energies of ∼10 keV. On the basis of these simultaneous ground‐satellite measurements, we discuss substorm onset models of reconnection/flow braking and near‐Earth plasma sheet instabilities.