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Laboratory measurements of the physics of auroral electron acceleration by Alfven waves
Journal article   Open access   Peer reviewed

Laboratory measurements of the physics of auroral electron acceleration by Alfven waves

J. W. R. Schroeder, G. G. Howes, C. A. Kletzing, F. Skiff, T. A. Carter, S. Vincena and S. Dorfman
Nature communications, Vol.12(1), 3103
06/07/2021
DOI: 10.1038/s41467-021-23377-5
PMCID: PMC8184961
PMID: 34099653
url
https://doi.org/10.1038/s41467-021-23377-5View
Published (Version of record) Open Access

Abstract

While the aurora has attracted attention for millennia, important questions remain unanswered. Foremost is how auroral electrons are accelerated before colliding with the ionosphere and producing auroral light. Powerful Alfven waves are often found traveling Earthward above auroras with sufficient energy to generate auroras, but there has been no direct measurement of the processes by which Alfven waves transfer their energy to auroral electrons. Here, we show laboratory measurements of the resonant transfer of energy from Alfven waves to electrons under conditions relevant to the auroral zone. Experiments are performed by launching Alfven waves and simultaneously recording the electron velocity distribution. Numerical simulations and analytical theory support that the measured energy transfer process produces accelerated electrons capable of reaching auroral energies. The experiments, theory, and simulations demonstrate a clear causal relationship between Alfven waves and accelerated electrons that directly cause auroras.
Multidisciplinary Sciences Science & Technology Science & Technology - Other Topics

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