University of Minnesota
School of Physics & Astronomy

Physics and Astronomy Calendar

Tuesday, February 28th 2017
12:20 pm:
Speaker: John Dombeck, Physics, U Minnesota
Subject: Field-Aligned Currents and Auroral Precipitation Mechanisms in the Earth's Magnetosphere

Field-aligned currents (FACs) provide a fundamental driver and means of Magnetosphere-Ionosphere (M-I) coupling. These currents need to be supported by local physics along the entire field line generally with quasi-static potential structures, but also to support the time-evolution of these structures and currents Alfvén waves are required which can produce Alfvénic electron acceleration. In regions of upward current, precipitating auroral electrons are accelerated earthward. These processes can result in ion outflow, changes
in ionospheric conductivity, and affect the particle distributions on the field line, affecting the M-I coupling processes supporting the individual FACs and potentially the entire FAC system. The FAST mission was well suited to study both the FACs and the electron auroral acceleration processes. We present the results of the comparisons between meso- and small-scale FACs determined from FAST using the method of Peria, et al., 2000, and our FAST auroral acceleration mechanism study when such identification is possible for the entire ~13 year FAST mission.

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