AAS 200th meeting, Albuquerque, NM, June 2002
Session 57. Living with a Star
Display, Wednesday, June 5, 2002, 10:00am-7:00pm, SW Exhibit Hall

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[57.13] A theoretical model for O+5 (O+7) ions in the fast solar wind

Y. Chen, R. Esser (Harvard-Smithsonian Center for Astrophysics), Y. Hu (University of Science and Technology of China)

We present a theoretical model for O+5 (O+7) ions as test particles in the fast solar wind, using a previous turbulence-driven four-fluid model to establish the background solar wind which consists of electrons, protons, alpha particles and O+6 ions. The O+5 (O+7) ions in our model and the O+6 ions in the background are driven by the same mechanism, say, the resonant cyclotron interaction or artificial heating additions. The ionization and recombination processes of O ions are taken into account. It is shown that the differential flow speeds between O+6 and O+5 or O+7, which are found to be in the range of 0.3 to 2, play very different roles in the formation of O charge states. This is due to discrepancy between the freezing-in distances of the two ion species. O+7 forms predominantly below 1.2 RS too close to the Sun to develop a differential streaming between O ions. O+5 on the other hand, freezes-in at about 1.8 RS where differential flows are well developed and therefore important for the formation of O+5 ions.

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Bulletin of the American Astronomical Society, 34
© 2002. The American Astronomical Soceity.