HR: 1340h
AN: SH43A-1081    [Abstracts]
TI: Long-wavelength velocity oscillations in the outer heliosphere
AU: * Ao, X
EM: xao001@student.ucr.edu
AF: IGPP, University of California, Riverside, CA 92521 United States
AU: Zank, G P
EM: zank@ucr.edu
AF: IGPP, University of California, Riverside, CA 92521 United States
AU: Richardson, J
EM: jdr@space.mit.edu
AF: Center for Space Research, Massachusetts Institute of Technology, Cambridge, MA 02139 United States
AB: Voyager 2 detected unusual long-wavelength, low frequency velocity oscillations in the solar wind with a period of 2.3 days and peak to trough amplitudes that ranged from 10 km/s - 20 km/s [Paularena et al., 1996]. Since the observed oscillatory features had not yet merged, Paularena et al concluded that the waves had been generated comparatively near Voyager 2 in the outer heliosphere. Three possibilities for the excitation of these waves were suggested, none of which were convincing except that it was somehow associated with pickup ions. We present a simple model for wave excitation driven by pickup ion pressure in the outer heliosphere that appears to account for the observations. Examples of the theoretical model are compared directly to the observed velocity oscillations and we find very reasonable agreement.
DE: 2149 MHD waves and turbulence
DE: 2152 Pickup ions
SC: SPA-Solar and Heliospheric Physics [SH]
MN: 2004 AGU Fall Meeting