Science Seminars

1/29/2015 – Understanding Electron-Hole Instabilities in the Lunar Plasma Wake

Speaker: Ian Hutchinson (MIT)
Date: Wednesday, Jan 29, 2020
Time: 4:00 PM
Location: SPSC W120

Seminar Abstract:

The moon, like many objects in flowing plasma, gives rise to a rarefied quasineutral plasma wake that attracts ions along the magnetic field giving rise to beam-like ion distributions, known theoretically since the 1960s, and observed by satelites. Recent particle in cell simulations of the wake at realistic mass ratio show ion-disrupting instabilities grow in regions where the ion streams are theoretically ion-ion _stable_. These turn out to be caused by the non-linear growth of electron holes generated not by the ion distribution but by a dimple in the electron distribution. The new hole growth mechanism responsible is hole drift into increasing background density plasma, which can be analysed analytically.