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Title: Regulation of ion drifts and anisotropies by parametrically unstable finite-amplitude Alfvén-cyclotron waves in the fast solar wind

We study the preferential heating and differential acceleration of minor ions by dissipation of ion-acoustic waves (IAWs) generated by parametric instabilities of a finite-amplitude monochromatic Alfvén-cyclotron pump wave. We consider the associated kinetic effects of Landau damping and nonlinear pitch-angle scattering of protons and α particles in the tenuous plasma of coronal holes and the fast solar wind. Various data collected by Wind spacecraft show signatures for a local transverse heating of the minor ions, presumably by Alfvén-cyclotron wave dissipation, and an unexpected parallel heating by a so far unknown mechanism. Here, we present the results from a set of 1.5 dimensional hybrid simulations in search for a plausible explanation for the observed field-aligned kinetic features in the fast solar wind minor ions. We investigate the origin and regulation of ion relative drifts and temperature anisotropies in low plasma β, fast solar wind conditions. Depending on their initial drifts, both ion species can heat up not only transversely through cyclotron resonance and non-resonant wave-particle interactions, but also strongly in the parallel direction by Landau damping of the daughter IAWs. We discuss the dependence of the relative ion drifts and temperature anisotropies on the plasma β of the individual species andmore » we describe the effect of the pump wave amplitude on the ion heating and acceleration.« less
Authors:
 [1] ;  [2] ;  [3]
  1. NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)
  2. Departamento de Física, Universidad de Concepción, 4070386 (Chile)
  3. Institute for Experimental and Applied Physics, Christian Albrechts University at Kiel, D-24118 Kiel (Germany)
Publication Date:
OSTI Identifier:
22351560
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 783; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ACCELERATION; ALFVEN WAVES; AMPLITUDES; ANISOTROPY; CYCLOTRON RESONANCE; HEATING; INCLINATION; ION DRIFT; IONS; LANDAU DAMPING; MONOCHROMATIC RADIATION; PARAMETRIC INSTABILITIES; PARTICLE INTERACTIONS; PLASMA; PROTONS; SCATTERING; SIMULATION; SOLAR WIND; SOUND WAVES; TURBULENCE