Wicks, RT;
Alexander, RL;
Stevens, M;
III, WLB;
Moya, PS;
Vinas, A;
Jian, LK;
... Zurbuchen, TH; + view all
(2016)
A proton-cyclotron wave storm generated by unstable proton distribution functions in the solar wind.
The Astrophysical Journal
, 819
(1)
, Article 6. 10.3847/0004-637X/819/1/6.
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Abstract
We use audification of 0.092 s cadence magnetometer data from the Wind spacecraft to identify waves with amplitudes >0.1 nT near the ion gyrofrequency (~0.1 Hz) with duration longer than 1 hr during 2008. We present one of the most common types of event for a case study and find it to be a proton-cyclotron wave storm, coinciding with highly radial magnetic field and a suprathermal proton beam close in density to the core distribution itself. Using linear Vlasov analysis, we conclude that the long-duration, large-amplitude waves are generated by the instability of the proton distribution function. The origin of the beam is unknown, but the radial field period is found in the trailing edge of a fast solar wind stream and resembles other events thought to be caused by magnetic field footpoint motion or interchange reconnection between coronal holes and closed field lines in the corona.
Type: | Article |
---|---|
Title: | A proton-cyclotron wave storm generated by unstable proton distribution functions in the solar wind |
Open access status: | An open access version is available from UCL Discovery |
DOI: | 10.3847/0004-637X/819/1/6 |
Publisher version: | http://dx.doi.org/10.3847/0004-637X/819/1/6 |
Language: | English |
Additional information: | Copyright © 2016. The American Astronomical Society. All rights reserved. |
Keywords: | instabilities, plasmas, solar wind, waves |
UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Space and Climate Physics UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Space and Climate Physics > Advanced Instrumentation Systems |
URI: | https://discovery-pp.ucl.ac.uk/id/eprint/1482211 |
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