Magnetosheath plasma expansion: Hybrid simulations
We investigate the effect of slow expansion on a magnetosheath plasma and low‐frequency waves using a two‐dimensional hybrid expanding box simulation. We start our simulation with a homogeneous high beta plasma, which is marginally stable to the mirror and proton cyclotron instabilities. The expansi...
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Published in | Geophysical research letters Vol. 34; no. 15; pp. L15104 - n/a |
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Main Authors | , , , , , |
Format | Journal Article |
Language | English |
Published |
Washington, DC
American Geophysical Union
01.08.2007
Blackwell Publishing Ltd |
Subjects | |
Online Access | Get full text |
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Summary: | We investigate the effect of slow expansion on a magnetosheath plasma and low‐frequency waves using a two‐dimensional hybrid expanding box simulation. We start our simulation with a homogeneous high beta plasma, which is marginally stable to the mirror and proton cyclotron instabilities. The expansion is imposed as an external force: the physical size of the simulation box increases in two dimensions: one parallel and one perpendicular with respect to the ambient magnetic field. This expansion leads to a continuous decrease of proton beta and drives an increase of the proton temperature anisotropy. In the early stages of the simulation, both mirror and proton cyclotron waves appear. The system establishes a marginally stable state with respect to both mirror and proton cyclotron instabilities. Initially, the mirror waves dominate the proton cyclotron waves, even when the system is below the linear mirror threshold, but as time increases the proton cyclotron waves become dominant in the low beta region. We also include an initial comparison of the simulated data with Cluster observations. |
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Bibliography: | ArticleID:2007GL029728 ark:/67375/WNG-979GL06G-Q istex:44275C8C1BC4D0D7AA4756F82CD740EA926902C2 ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0094-8276 1944-8007 |
DOI: | 10.1029/2007GL029728 |