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Title: On the generation of double layers from ion- and electron-acoustic instabilities

Abstract

A plasma double layer (DL) is a nonlinear electrostatic structure that carries a uni-polar electric field parallel to the background magnetic field due to local charge separation. Past studies showed that DLs observed in space plasmas are mostly associated with the ion acoustic instability. Recent Van Allen Probes observations of parallel electric field structures traveling much faster than the ion acoustic speed have motivated a computational study to test the hypothesis that a new type of DLs—electron acoustic DLs—generated from the electron acoustic instability are responsible for these electric fields. Nonlinear particle-in-cell simulations yield negative results, i.e., the hypothetical electron acoustic DLs cannot be formed in a way similar to ion acoustic DLs. Linear theory analysis and the simulations show that the frequencies of electron acoustic waves are too high for ions to respond and maintain charge separation required by DLs. However, our results do show that local density perturbations in a two-electron-component plasma can result in unipolar-like electric field structures that propagate at the electron thermal speed, suggesting another potential explanation for the observations.

Authors:
; ;  [1];  [2]
  1. Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)
  2. Space Science Institute, Boulder, Colorado 80301 (United States)
Publication Date:
OSTI Identifier:
22599039
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 23; Journal Issue: 3; Other Information: (c) 2016 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; DENSITY; DISTURBANCES; ELECTRIC FIELDS; ELECTRON PLASMA WAVES; ELECTRONS; INSTABILITY; IONS; LAYERS; MAGNETIC FIELDS; NONLINEAR PROBLEMS; PERTURBATION THEORY; SIMULATION; VELOCITY

Citation Formats

Fu, Xiangrong, E-mail: xrfu@lanl.gov, Cowee, Misa M., Winske, Dan, and Gary, S. Peter. On the generation of double layers from ion- and electron-acoustic instabilities. United States: N. p., 2016. Web. doi:10.1063/1.4943881.
Fu, Xiangrong, E-mail: xrfu@lanl.gov, Cowee, Misa M., Winske, Dan, & Gary, S. Peter. On the generation of double layers from ion- and electron-acoustic instabilities. United States. doi:10.1063/1.4943881.
Fu, Xiangrong, E-mail: xrfu@lanl.gov, Cowee, Misa M., Winske, Dan, and Gary, S. Peter. Tue . "On the generation of double layers from ion- and electron-acoustic instabilities". United States. doi:10.1063/1.4943881.
@article{osti_22599039,
title = {On the generation of double layers from ion- and electron-acoustic instabilities},
author = {Fu, Xiangrong, E-mail: xrfu@lanl.gov and Cowee, Misa M. and Winske, Dan and Gary, S. Peter},
abstractNote = {A plasma double layer (DL) is a nonlinear electrostatic structure that carries a uni-polar electric field parallel to the background magnetic field due to local charge separation. Past studies showed that DLs observed in space plasmas are mostly associated with the ion acoustic instability. Recent Van Allen Probes observations of parallel electric field structures traveling much faster than the ion acoustic speed have motivated a computational study to test the hypothesis that a new type of DLs—electron acoustic DLs—generated from the electron acoustic instability are responsible for these electric fields. Nonlinear particle-in-cell simulations yield negative results, i.e., the hypothetical electron acoustic DLs cannot be formed in a way similar to ion acoustic DLs. Linear theory analysis and the simulations show that the frequencies of electron acoustic waves are too high for ions to respond and maintain charge separation required by DLs. However, our results do show that local density perturbations in a two-electron-component plasma can result in unipolar-like electric field structures that propagate at the electron thermal speed, suggesting another potential explanation for the observations.},
doi = {10.1063/1.4943881},
journal = {Physics of Plasmas},
number = 3,
volume = 23,
place = {United States},
year = {Tue Mar 15 00:00:00 EDT 2016},
month = {Tue Mar 15 00:00:00 EDT 2016}
}