DISSIPATION OF PARALLEL AND OBLIQUE ALFVÉN-CYCLOTRON WAVES—IMPLICATIONS FOR HEATING OF ALPHA PARTICLES IN THE SOLAR WIND

Y. G. Maneva, Adolfo F. Viñas, Pablo S. Moya, Robert T. Wicks, Stefaan Poedts

Research output: Contribution to journalArticlepeer-review

14 Citations (Scopus)

Abstract

We perform 2.5D hybrid simulations with massless fluid electrons and kinetic particle-in-cell ions to study the temporal evolution of ion temperatures, temperature anisotropies, and velocity distribution functions in relation to the dissipation and turbulent evolution of a broadband spectrum of parallel and obliquely propagating Alfvén-cyclotron waves. The purpose of this paper is to study the relative role of parallel versus oblique Alfvén-cyclotron waves in the observed heating and acceleration of alpha particles in the fast solar wind. We consider collisionless homogeneous multi-species plasma, consisting of isothermal electrons, isotropic protons, and a minor component of drifting α particles in a finite-β fast stream near the Earth. The kinetic ions are modeled by initially isotropic Maxwellian velocity distribution functions, which develop nonthermal features and temperature anisotropies when a broadband spectrum of low-frequency nonresonant, ω ≤ 0.34 Ωp, Alfvén-cyclotron waves is imposed at the beginning of the simulations. The initial plasma parameter values, such as ion density, temperatures, and relative drift speeds, are supplied by fast solar wind observations made by the Wind spacecraft at 1 AU. The imposed broadband wave spectra are left-hand polarized and resemble Wind measurements of Alfvénic turbulence in the solar wind. The imposed magnetic field fluctuations for all cases are within the inertial range of the solar wind turbulence and have a Kraichnan-type spectral slope α = −3/2. We vary the propagation angle from θ = 0° to θ = 30° and θ = 60°, and find that the heating of alpha particles is most efficient for the highly oblique waves propagating at 60°, whereas the protons exhibit perpendicular cooling at all propagation angles.
Original languageEnglish
Pages (from-to)33-49
Number of pages15
JournalThe Astrophysical Journal
Volume814
Issue number1
Early online date13 Nov 2015
DOIs
Publication statusPublished - Nov 2015
Externally publishedYes

Fingerprint

Dive into the research topics of 'DISSIPATION OF PARALLEL AND OBLIQUE ALFVÉN-CYCLOTRON WAVES—IMPLICATIONS FOR HEATING OF ALPHA PARTICLES IN THE SOLAR WIND'. Together they form a unique fingerprint.

Cite this