Hybrid models of solar wind plasma heating
- 1Department of Physics, The Catholic University of America, Washington, D.C. 20064, USA
- 2NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA
- 3Departamento de Fisica, Facultad de Ciencias, Universidad de Chile, Las Palmeras 3425, Casilla 653, Santiago, Chile
- *visiting: Dept. of Geophysics and Planetary Sciences, Tel Aviv University, Tel Aviv, Israel
Abstract. Remote sensing and in-situ observations show that solar wind ions are often hotter than electrons, and the heavy ions flow faster than the protons by up to an Alfvén speed. Turbulent spectrum of Alfvénic fluctuations and shocks were detected in solar wind plasma. Cross-field inhomogeneities in the corona were observed to extend to several tens of solar radii from the Sun. The acceleration and heating of solar wind plasma is studied via 1-D and 2-D hybrid simulations. The models describe the kinetics of protons and heavy ions, and electrons are treated as neutralizing fluid.The expansion of the solar wind is considered in 1-D hybrid model. A spectrum of Alfvénic fluctuations is injected at the computational boundary, produced by differential streaming instability, or initial ion temperature anisotropy, and the parametric dependence of the perpendicular heating of H+-He++ solar wind plasma is studied. It is found that He++ ions are heated efficiently by the Alfvénic wave spectrum below the proton gyroperiod.