Ion collisional transport coefficients in the solar wind at 1 AU

Abstract

Proton and alpha particle collisional transport coefficients (isotropization, relative deceleration frequencies and heating rates) at 1 AU are quantified using the WIND/SWE data. In agreement with previous studies the ion-ion Coulomb collisions are generally important for slow solar wind streams and tend to reduce the temperature anisotropies, the differential streaming and the differences between proton and alpha particle temperatures. In slow solar wind streams the Coulomb collisions between protons and alpha particles are important for the overall proton energetics as well as for the relative deceleration between the two species. It is also shown that ion temperature anisotropies and differential streaming need to be generally taken into account for evaluation of the collisional transport coefficients.

ApJ, 5 pages, 4 figures

References in corpus (4)

• Ensemble Simulations of Proton Heating in the Solar Wind via Turbulence and Ion Cyclotron Resonance
• Collisional Thermalization of Hydrogen and Helium in Solar Wind Plasma
• Solar wind protons at 1 AU: trends and bounds, constraints and correlations
• Deceleration of Alpha Particles in the Solar Wind by Instabilities and the Rotational Force: Implications for Heating, Azimuthal Flow, and the Parker Spiral Magnetic Field

Cited by in corpus (4)

• The multi-scale nature of the solar wind
• A zone of preferential ion heating extends tens of solar radii from Sun
• Radial evolution of the solar wind in pure high-speed streams: HELIOS revised observations
• Proton heating by pick-up ion driven cyclotron waves in the outer heliosphere: Hybrid expanding box simulations