HR: 0800h
AN: SH51C-0281    [Abstracts]
TI: Heating and Acceleration of Minor Ions in the Expanding Solar Wind
AU: * Hellinger, P
EM: Petr.Hellinger@ufa.cas.cz
AF: Institute of Atmospheric Physics, AS CR, Bocni II/1401, Prague, 14131 Czech Republic
AU: * Hellinger, P
EM: Petr.Hellinger@ufa.cas.cz
AF: Department of Astrophysics and Space Science, University of Florence, Lago E.Fermi, 5, Florence, 50125 Italy
AU: Velli, M
EM: velli@arcetri.astro.it
AF: Department of Astrophysics and Space Science, University of Florence, Lago E.Fermi, 5, Florence, 50125 Italy
AU: Velli, M
EM: velli@arcetri.astro.it
AF: Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91109 United States
AU: Travnicek, P
EM: trav@alenka.ufa.cas.cz
AF: Institute of Atmospheric Physics, AS CR, Bocni II/1401, Prague, 14131 Czech Republic
AU: Goldstein, B E
EM: bruce.goldstein@jpl.nasa.gov
AF: Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91109 United States
AU: Liewer, P C
EM: paulett.liewer@jpl.nasa.gov
AF: Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91109 United States
AB: We present hybrid simulations of the interaction of Alfven waves with protons, alpha particles and a small abundance of oxygen 5+ using the expanding box model. The simulations test the sweeping mechanism of the heating and acceleration of the solar wind by cyclotron resonance with Alfven waves. The numerical simulations indicate that oxygen (and other minor ions) are efficiently heated in perpendicular direction and accelerated but are able to absorb only a limited amount of available energy in the Alfven waves. The presence of oxygen ions has a minimal influence on alpha particles and protons. However, for the parameters used in the simulations the heating and acceleration of alpha particles and protons are not very efficient. We also explore the role of the radial stretching which occurs in the acceleration region of the wind. This amounts to an expansion of the box also in the radial direction and leads to important parallel cooling. The combination of the perpendicular heating by Alfven wave and the parallel cooling induced by the radial expansion leads to the strong temperature anisotropies of oxygen ions. The simulations are discussed within the context of observations and theoretical models of the evolution of MHD turbulence and ion thermodynamics in the outer corona and accelerating solar wind.
DE: 7807 Charged particle motion and acceleration
DE: 7843 Numerical simulation studies
DE: 7867 Wave/particle interactions
DE: 2149 MHD waves and turbulence
DE: 2164 Solar wind plasma
SC: SPA-Solar and Heliospheric Physics [SH]
MN: 2004 AGU Fall Meeting