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Title: Whistler turbulence heating of electrons and ions: Three-dimensional particle-in-cell simuations

In this study, the decay of whistler turbulence in a collisionless, homogeneous, magnetized plasma is studied using three-dimensional particle-in-cell simulations. The simulations are initialized with a narrowband, relatively isotropic distribution of long wavelength whistler modes. A first ensemble of simulations at electron beta $${\beta }_{{\rm{e}}}$$ = 0.25 and ion-to-electron mass ratio $${m}_{{\rm{i}}}$$/$${m}_{{\rm{e}}}$$ = 400 is carried out on a domain cube of dimension $$L{\omega }_{\mathrm{pi}}$$/c = 5.12 where $${\omega }_{\mathrm{pi}}$$ is the ion plasma frequency. The simulations begin with a range of dimensionless fluctuating field energy densities, $${\epsilon }_{{\rm{o}}}$$, and follow the fluctuations as they cascade to broadband, anisotropic turbulence which dissipates at shorter wavelengths, heating both electrons and ions. The electron heating is stronger and preferentially parallel/antiparallel to the background magnetic field $${{\boldsymbol{B}}}_{{\rm{o}}};$$ the ion energy gain is weaker and is preferentially in directions perpendicular to $${{\boldsymbol{B}}}_{{\rm{o}}}$$. The important new results here are that, over 0.01 < $${\epsilon }_{{\rm{o}}}$$ < 0.25, the maximum rate of electron heating scales approximately as $${\epsilon }_{{\rm{o}}}$$, and the maximum rate of ion heating scales approximately as $${\epsilon }_{{\rm{o}}}^{1.5}$$. A second ensemble of simulations at $${\epsilon }_{{\rm{o}}}$$ = 0.10 and $${\beta }_{{\rm{e}}}$$ = 0.25 shows that, over 25 < $${m}_{{\rm{i}}}$$/$${m}_{{\rm{e}}}\;$$< 1836, the ratio of the maximum ion heating rate to the maximum electron heating rate scales approximately as $${m}_{{\rm{e}}}$$/$${m}_{{\rm{i}}}$$.
Authors:
 [1] ;  [2] ;  [2]
  1. Space Science Institute, Boulder, CO (United States)
  2. Univ. of Southern California, Los Angeles, CA (United States)
Publication Date:
Report Number(s):
LA-UR-15-27211
Journal ID: ISSN 1538-4357
Grant/Contract Number:
AC52-06NA25396
Type:
Accepted Manuscript
Journal Name:
The Astrophysical Journal (Online)
Additional Journal Information:
Journal Name: The Astrophysical Journal (Online); Journal Volume: 816; Journal Issue: 2; Journal ID: ISSN 1538-4357
Publisher:
Institute of Physics (IOP)
Research Org:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; turbulence; simulations; plasmas; solar wind
OSTI Identifier:
1255083

Gary, S. Peter, Hughes, R. Scott, and Wang, Joseph. Whistler turbulence heating of electrons and ions: Three-dimensional particle-in-cell simuations. United States: N. p., Web. doi:10.3847/0004-637X/816/2/102.
Gary, S. Peter, Hughes, R. Scott, & Wang, Joseph. Whistler turbulence heating of electrons and ions: Three-dimensional particle-in-cell simuations. United States. doi:10.3847/0004-637X/816/2/102.
Gary, S. Peter, Hughes, R. Scott, and Wang, Joseph. 2016. "Whistler turbulence heating of electrons and ions: Three-dimensional particle-in-cell simuations". United States. doi:10.3847/0004-637X/816/2/102. https://www.osti.gov/servlets/purl/1255083.
@article{osti_1255083,
title = {Whistler turbulence heating of electrons and ions: Three-dimensional particle-in-cell simuations},
author = {Gary, S. Peter and Hughes, R. Scott and Wang, Joseph},
abstractNote = {In this study, the decay of whistler turbulence in a collisionless, homogeneous, magnetized plasma is studied using three-dimensional particle-in-cell simulations. The simulations are initialized with a narrowband, relatively isotropic distribution of long wavelength whistler modes. A first ensemble of simulations at electron beta ${\beta }_{{\rm{e}}}$ = 0.25 and ion-to-electron mass ratio ${m}_{{\rm{i}}}$/${m}_{{\rm{e}}}$ = 400 is carried out on a domain cube of dimension $L{\omega }_{\mathrm{pi}}$/c = 5.12 where ${\omega }_{\mathrm{pi}}$ is the ion plasma frequency. The simulations begin with a range of dimensionless fluctuating field energy densities, ${\epsilon }_{{\rm{o}}}$, and follow the fluctuations as they cascade to broadband, anisotropic turbulence which dissipates at shorter wavelengths, heating both electrons and ions. The electron heating is stronger and preferentially parallel/antiparallel to the background magnetic field ${{\boldsymbol{B}}}_{{\rm{o}}};$ the ion energy gain is weaker and is preferentially in directions perpendicular to ${{\boldsymbol{B}}}_{{\rm{o}}}$. The important new results here are that, over 0.01 < ${\epsilon }_{{\rm{o}}}$ < 0.25, the maximum rate of electron heating scales approximately as ${\epsilon }_{{\rm{o}}}$, and the maximum rate of ion heating scales approximately as ${\epsilon }_{{\rm{o}}}^{1.5}$. A second ensemble of simulations at ${\epsilon }_{{\rm{o}}}$ = 0.10 and ${\beta }_{{\rm{e}}}$ = 0.25 shows that, over 25 < ${m}_{{\rm{i}}}$/${m}_{{\rm{e}}}\;$< 1836, the ratio of the maximum ion heating rate to the maximum electron heating rate scales approximately as ${m}_{{\rm{e}}}$/${m}_{{\rm{i}}}$.},
doi = {10.3847/0004-637X/816/2/102},
journal = {The Astrophysical Journal (Online)},
number = 2,
volume = 816,
place = {United States},
year = {2016},
month = {1}
}