Prediction and Observation of Electron Instabilities and Phase Space Holes Concentrated in the Lunar Plasma Wake

Recent theory and numerical simulation predicts that the wake of the solar wind flow past the Moon should be the site of electrostatic instabilities that give rise to electron holes. These play an important role in the eventual merging of the wake with the background solar wind. Analysis of measurem...

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Bibliographic Details
Main Authors: Malaspina, David M., Hutchinson, Ian Horner
Other Authors: Massachusetts Institute of Technology. Plasma Science and Fusion Center
Format: Article
Language:en_US
Published: American Geophysical Union (AGU) 2018
Online Access:http://hdl.handle.net/1721.1/118896
Description
Summary:Recent theory and numerical simulation predicts that the wake of the solar wind flow past the Moon should be the site of electrostatic instabilities that give rise to electron holes. These play an important role in the eventual merging of the wake with the background solar wind. Analysis of measurements from the ARTEMIS satellites, orbiting the Moon at distances from 1.2 to 11 R[subscript M], detects holes highly concentrated in the wake, in agreement with prediction. The theory also predicts that the hole flux density observed should be hollow, peaking away from the wake axis. Observation statistics qualitatively confirm this hollowness, lending extra supporting evidence for the identification of their generation mechanism. Keywords: lunar wake; solar wind; electron hole; electrostatic instability; ARTEMIS