Oblate electron holes are not attributable to anisotropic shielding
Name
21ja102_full.pdf
Size
2.54 MB
Format
Adobe PDF
Checksum (MD5)
412246a4e3e55c753acbec1c58b5cd64
Author(s)
Hutchinson, Ian H.
Date Issued
February 2021
Journal
Physics of Plasmas
Publisher
AIP
Abstract
Shielding mechanisms' influence on the ratio of perpendicular to parallel scale lengths of multidimensional plasma electron hole equilibria are analyzed theoretically and computationally. It is shown that the ``gyrokinetic'' model, invoking perpendicular polarization, is based on a misunderstanding and cannot explain the observational trend that greater transverse extent accompanies lower magnetic field. Instead, the potential in the wings of the hole, outside the region of trapped-electron depletion, has isotropic shielding giving $\phi\propto {\rm e}^{-r/L}/r$, with the shielding length $L$ equal to the Debye length for holes much slower than the electron thermal speed. Particle in cell simulations confirm the analysis. Trapped electron charge distribution anisotropy must therefore instead underlie the oblate shape of electron holes.
Description
Submitted for publication in Physics of Plasmas
MIT Department
Massachusetts Institute of Technology. Plasma Science and Fusion Center
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1063/5.0039233
