UCL Discovery
UCL home » Library Services » Electronic resources » UCL Discovery

Dissipation of parallel and oblique Alfvén-cyclotron waves - implications for heating of alpha particles in the solar wind

Maneva, YG; Viñas, AF; Moya, PS; Wicks, RT; Poedts, S; (2015) Dissipation of parallel and oblique Alfvén-cyclotron waves - implications for heating of alpha particles in the solar wind. The Astrophysical Journal , 814 (1) , Article 33. 10.1088/0004-637X/814/1/33. Green open access

[thumbnail of apj_814_1_33.pdf]
Preview
Text
apj_814_1_33.pdf - Published Version

Download (10MB) | Preview

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.

Type: Article
Title: Dissipation of parallel and oblique Alfvén-cyclotron waves - implications for heating of alpha particles in the solar wind
Open access status: An open access version is available from UCL Discovery
DOI: 10.1088/0004-637X/814/1/33
Publisher version: http://dx.doi.org/10.1088/0004-637X/814/1/33
Language: English
Additional information: Copyright © 2015. The American Astronomical Society. All rights reserved.
UCL classification: UCL
UCL > Provost and Vice Provost Offices > UCL BEAMS
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Space and Climate Physics
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Space and Climate Physics > Advanced Instrumentation Systems
URI: https://discovery.ucl.ac.uk/id/eprint/1482215
Downloads since deposit
95Downloads
Download activity - last month
Download activity - last 12 months
Downloads by country - last 12 months

Archive Staff Only

View Item View Item