Magnetic Fluctuation Power Near Proton Temperature Anisotropy Instability Thresholds in the Solar Wind

S. D Bale; J. C Kasper; G. G Howes; E Quataert; C Salem; D Sundkvist

doi:10.1103/PHYSREVLETT.103.211101

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Magnetic Fluctuation Power Near Proton Temperature Anisotropy Instability Thresholds in the Solar Wind

Journal article

Peer reviewed

Magnetic Fluctuation Power Near Proton Temperature Anisotropy Instability Thresholds in the Solar Wind

S. D Bale, J. C Kasper, G. G Howes, E Quataert, C Salem and D Sundkvist

Physical review letters, Vol.103(21), pp.211101-211101

11/20/2009

DOI: 10.1103/PHYSREVLETT.103.211101

PMID: 20366024

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https://arxiv.org/pdf/0908.1274View

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Abstract

The proton temperature anisotropy in the solar wind is known to be constrained by the theoretical thresholds for pressure-anisotropy-driven instabilities. Here, we use approximately 1x10{sup 6} independent measurements of gyroscale magnetic fluctuations in the solar wind to show for the first time that these fluctuations are enhanced along the temperature anisotropy thresholds of the mirror, proton oblique firehose, and ion cyclotron instabilities. In addition, the measured magnetic compressibility is enhanced at high plasma beta (beta{sub ||} > or approx. 1) along the mirror instability threshold but small elsewhere, consistent with expectations of the mirror mode. We also show that the short wavelength magnetic fluctuation power is a strong function of collisionality, which relaxes the temperature anisotropy away from the instability conditions and reduces correspondingly the fluctuation power.

ANISOTROPY

ASTROPHYSICS, COSMOLOGY AND ASTRONOMY

BARYONS

CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS

COMPRESSIBILITY

CYCLOTRON INSTABILITY

ELEMENTARY PARTICLES

FERMIONS

FLUCTUATIONS

HADRONS

INSTABILITY

MECHANICAL PROPERTIES

NUCLEONS

PLASMA

PLASMA INSTABILITY

PLASMA MICROINSTABILITIES

PROTON TEMPERATURE

PROTONS

SOLAR ACTIVITY

SOLAR WIND

STELLAR ACTIVITY

STELLAR WINDS

VARIATIONS

WAVELENGTHS

Details

Title: Subtitle: Magnetic Fluctuation Power Near Proton Temperature Anisotropy Instability Thresholds in the Solar Wind
Creators: S. D Bale - University of California, Berkeley
J. C Kasper - Harvard University
G. G Howes - University of Iowa
E Quataert - University of California, Berkeley
C Salem - University of California, Berkeley
D Sundkvist - University of California, Berkeley
Resource Type: Journal article
Publication Details: Physical review letters, Vol.103(21), pp.211101-211101
DOI: 10.1103/PHYSREVLETT.103.211101
PMID: 20366024
NLM abbreviation: Phys Rev Lett
ISSN: 0031-9007
eISSN: 1079-7114
Language: English
Date published: 11/20/2009
Academic Unit: Physics and Astronomy
Record Identifier: 9984200058302771

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