HR: 0800h
AN: SH11B-0264    [Abstracts]
TI: The Occurrence Rate of Solar Wind Periodic Number Density Structures
AU: * Viall, N M
EM: nickiv@bu.edu
AF: Boston University Astronomy Dept., 725 commonwealth ave, room 506, Boston, MA 02215
AU: Kepko, L
EM: lkepko@bu.edu
AF: Boston University Astronomy Dept., 725 commonwealth ave, room 506, Boston, MA 02215
AU: Spence, H
EM: spence@bu.edu
AF: Boston University Astronomy Dept., 725 commonwealth ave, room 506, Boston, MA 02215
AB: The solar wind is generally described as a fully turbulent plasma, with a featureless power-law spectrum that does not contain excess power at discrete frequencies. However, recent observations have indicated that the solar wind sometimes contains highly periodic number density variations in the mHz range in the Earth's reference frame. These periodic structures remained coherent over several hours and were highly geoeffective, driving global magnetospheric oscillations at the same discrete frequencies. These previous studies examined only a few events, and did not determine the occurrence rate of these structures. In this paper we determine the occurrence rate of discrete oscillations in the solar wind number density. We perform a multi-tapered analysis for spectral estimation and robust significance testing using several years of solar wind data. In addition we attempt to reconcile the turbulent picture of the solar wind with the new observations.
DE: 2164 Solar wind plasma
DE: 2784 Solar wind/magnetosphere interactions
SC: SPA-Solar and Heliospheric Physics [SH]
MN: Fall Meeting 2005