Two-fluid 2.5D MHD Simulations of the Fast Solar Wind in Coronal Holes and the Relation to UVCS Observations |
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Authors: | J M Davila L Ofman |
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Institution: | (1) NASA GSFC, Code 682, Greenbelt, MD 20771, USA |
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Abstract: | Recent SOHO/UVCS observations indicate that the perpendicular proton and ion temperatures are much larger than electron temperatures.
In the present study we simulate numerically the solar wind flow in a coronal hole with the two-fluid approach. We investigate
the effects of electron and proton temperatures on the solar wind acceleration by nonlinear waves. In the model the nonlinear
waves are generated by Alfvén waves with frequencies in the 10-3 Hz range, driven at the base of the coronal hole. The resulting electron and proton flow profile exhibits density and velocity
fluctuations. The fluctuations may steepen into shocks as they propagate away from the sun. We calculate the effective proton
temperature by combining the thermal and wave velocity of the protons, and find qualitative agreement with the proton kinetic
temperature increase with height deduced from the UVCS Ly-α observations by Kohl et al. (1998).
This revised version was published online in June 2006 with corrections to the Cover Date. |
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