Identifying the magnetospheric driver of STEVE

Xiangning Chu; David Malaspina; Bea Gallardo-Lacourt; Jun Liang; Laila Andersson; Qianli Ma; Anton Artemyev; Jiang Liu; Bob Ergun; Scott Thaller; Hassanali Akbari; Hong Zhao; Brian Larsen; Geoffrey Reeves; John Wygant; Aaron Breneman; Sheng Tian; Martin Connors; Eric Donovan; William Archer; Elizabeth A. MacDonald

arXiv · 1906.08886

Identifying the magnetospheric driver of STEVE

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Abstract

For the first time, we identify the magnetospheric driver of STEVE, east-west aligned narrow emissions in the subauroral region. In the ionosphere, STEVE is associated with subauroral ion drift (SAID) features of high electron temperature peak, density gradient, and strong westward ion flow. In this study, we present STEVE's magnetospheric driver region at a sharp plasmapause containing: strong tailward quasi-static electric field, kinetic Alfven waves, parallel electron acceleration, perpendicular ion drift. The observed continuous emissions of STEVE are possibly caused by ionospheric electron heating due to heat conduction and/or auroral acceleration process powered by Alfven waves, both driven by the observed equatorial magnetospheric processes. The observed green emissions are likely optical manifestations of electron precipitations associated with wave structures traveling along the plasmapause. The observed SAR arc at lower latitudes likely corresponds to the formation of low-energy plasma inside the plasmapause by Coulomb collisions between ring current ions and plasmaspheric plasma.

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Xiangning Chu, David Malaspina, Bea Gallardo-Lacourt, Jun Liang, Laila Andersson, Qianli Ma, Anton Artemyev, Jiang Liu, Bob Ergun, Scott Thaller, Hassanali Akbari, Hong Zhao, Brian Larsen, Geoffrey Reeves, John Wygant, Aaron Breneman, Sheng Tian, Martin Connors, Eric Donovan, William Archer, Elizabeth A. MacDonald. 2019-06-20. Identifying the magnetospheric driver of STEVE. https://arxiv.org/abs/1906.08886

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