HR: 1340h
AN: SM23A-1193    [Abstracts]
TI: Pi1B Pulsations and Fast Flows
AU: * Argall, M R
EM: mry27@unh.edu
AF: University of New Hampshire, 39 College Rd, Durham, NH 03824, United States
AU: Lessard, M
EM: marc.lessard@unh.edu
AF: University of New Hampshire, 39 College Rd, Durham, NH 03824, United States
AU: Kim, H
EM: hyomin.kim@unh.edu
AF: University of New Hampshire, 39 College Rd, Durham, NH 03824, United States
AU: Mouikis, C
EM: chris.mouikis@unh.edu
AF: University of New Hampshire, 39 College Rd, Durham, NH 03824, United States
AU: Smith, C
EM: charles.smith@unh.edu
AF: University of New Hampshire, 39 College Rd, Durham, NH 03824, United States
AU: Engebretsen, M
EM: engebret@augsburg.edu
AF: Augsburg College, 2211 Riverside Ave., Minneapolis, MN 55454, United States
AU: Rogers, B
AF: Dartmouth College, 6127 Wilder Laboratory, Hanover, NH 03755, United States
AB: Pi1B pulsations are a type of ULF wave historically observed on the ground, having a relatively broadband signature with frequencies of a few Hz and below. Recently, these waves have also been observed in space. One case study concludes that the waves propagate from geosynchronous orbit (or beyond) to the ionosphere, while numerical efforts illustrate how such waves (which are compressional at geosynchronous orbit) become transverse at low (i.e., FAST) altitudes. In addition, a detailed study has been undertaken that relates observations of these waves in the magnetotail to fast flows. Specifically, it has been determined that Pi1B pulsations, as observed by Cluster and other spacecraft in the magnetotail, are precisely the magnetic signatures of fast flows. This conclusion begs the question of why fast flows should have such a signature, which of course is related to the nature of fast flows in general. In this presentation, this question is addressed both analytically and numerically, with efforts focusing on understanding the nature of a pressure pulse that is often observed with a reconnection model. Initial results show that the pressure pulse propagates at or near the Alfven speed and that it has a scale size the order of the ion skin depth, characteristics that are both comparable to observations of fast flows. Reports that fast flows are turbulent structures are also consistent with what would be expected numerically.
DE: 2723 Magnetic reconnection (7526, 7835)
DE: 2736 Magnetosphere/ionosphere interactions (2431)
DE: 2772 Plasma waves and instabilities (2471)
DE: 2788 Magnetic storms and substorms (7954)
SC: SPA-Magnetospheric Physics [SM]
MN: 2007 Fall Meeting