Energy source for auroral electrons from two proposed substorm onset processes
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In this paper, the authors examined the electron energy spectrum and the associated total field-aligned energy flux during six current disruption/dipolarization (CDD) events and compared them with five magnetic reconnection (MR) events.Abstract:
[1] There are two main processes in the tail that are proposed to link electron precipitation for the initial brightening auroral arc at substorm onset. These are current disruption/dipolarization (CDD) and magnetic reconnection (MR). To provide further clues in differentiating these two processes, we examine the electron energy spectrum and the associated total field-aligned energy flux during six CDD events and compare them with five MR events. Data from the Active Magnetospheric Particle Tracer Explorers/Charge Composition Explorer (AMPTE/CCE), Geotail, and Time History of Events and Macroscale Ineractions during Substorms (THEMIS) missions are used in this study. It is found that (1) the total field-aligned electron energy flux from CDD sites is generally high enough to account for the energy flux required to produce bright auroral arcs at substorm onsets and (2) the total field-aligned electron energy flux from MR sites is generally a factor of one to two orders of magnitude lower than that from CDD sites. These results favor a direct link between the CDD sites and the substorm onset arcs, but they do not rule out further acceleration of auroral electrons away from these sites by other energy sources (e.g., field-aligned potential drops and kinetic Alfven waves) to produce even higher-intensity auroral arcs.read more
Citations
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Generic model for magnetic explosions applied to solar flares
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Physical Processes for Magnetospheric Substorm Expansion Onsets
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References
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Journal ArticleDOI
The development of the auroral substorm.
TL;DR: In this paper, a working model of simultaneous auroral activity over the entire polar region is presented in terms of the auroral substorm, which has two characteristic phases, an expansive phase and a recovery phase.
Journal ArticleDOI
The THEMIS Mission
TL;DR: The Time History of Events and Macroscale Interactions during Substorms (THEMIS) mission is the fifth NASA Medium-class Explorer (MIDEX), launched on February 17, 2007 to determine the trigger and large-scale evolution of substorms as discussed by the authors.
Journal ArticleDOI
Tail reconnection triggering substorm onset.
Vassilis Angelopoulos,James P. McFadden,Davin Larson,C. W. Carlson,Stephen B. Mende,Harald U. Frey,Tai Phan,David G. Sibeck,Karl-Heinz Glassmeier,Uli Auster,Eric Donovan,Ian R. Mann,I. Jonathan Rae,Christopher T. Russell,Andrei Runov,Xu-Zhi Zhou,Larry Kepko +16 more
TL;DR: Results demonstrate that substorms are likely initiated by tail reconnection, and are reported on simultaneous measurements in the magnetotail at multiple distances, at the time of substorm onset.
Journal ArticleDOI
Structure and dynamics of magnetic reconnection for substorm onsets with Geotail observations
T. Nagai,M. Fujimoto,Yoshitaka Saito,Shinobu Machida,Toshio Terasawa,Rumi Nakamura,Tadashi Yamamoto,Toshifumi Mukai,Atsuhiro Nishida,Susumu Kokubun +9 more
TL;DR: In this paper, the structure and dynamics of magnetic reconnection were studied in the premidnight sector of the magnetotail at 20-30 RE for substorm onsets in Geotail observations.