Simulation and quasilinear theory of proton firehose instability

Journal Article · Thu Jan 15 04:00:00 EST 2015 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.4905230· OSTI ID:22407989

Seough, Jungjoon ^[1]; Yoon, Peter H. ^[2]; Hwang, Junga ^[1]

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1. Korean Astronomy and Space Science Institute, Daejeon (Korea, Republic of)
2. University of Maryland, College Park, Maryland 20742 (United States)

The electromagnetic proton firehose instability is driven by excessive parallel temperature anisotropy, T{sub ∥} > T{sub ⊥} (or more precisely, parallel pressure anisotropy, P{sub ∥} > P{sub ⊥}) in high-beta plasmas. Together with kinetic instabilities driven by excessive perpendicular temperature anisotropy, namely, electromagnetic proton cyclotron and mirror instabilities, its role in providing the upper limit for the temperature anisotropy in the solar wind is well-known. A recent Letter [Seough et al., Phys. Rev. Lett. 110, 071103 (2013)] employed quasilinear kinetic theory for these instabilities to explain the observed temperature anisotropy upper bound in the solar wind. However, the validity of quasilinear approach has not been rigorously tested until recently. In a recent paper [Seough et al., Phys. Plasmas 21, 062118 (2014)], a comparative study is carried out for the first time in which quasilinear theory of proton cyclotron instability is tested against results obtained from the particle-in-cell simulation method, and it was demonstrated that the agreement was rather excellent. The present paper addresses the same issue involving the proton firehose instability. Unlike the proton cyclotron instability, however, it is found that the quasilinear approximation enjoys only a limited range of validity, especially for the wave dynamics and for the relatively high-beta regime. Possible causes and mechanisms responsible for the discrepancies are speculated and discussed.

• OSTI ID: 22407989
• Journal Information: Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 1 Vol. 22; ISSN PHPAEN; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

43 PARTICLE ACCELERATORS
70 PLASMA PHYSICS AND FUSION TECHNOLOGY
ANISOTROPY
COMPUTERIZED SIMULATION
CYCLOTRON INSTABILITY
CYCLOTRONS
HIGH-BETA PLASMA
HOSE INSTABILITY
MIRRORS
PROTONS
QUASILINEAR PROBLEMS
SOLAR WIND