HR: 1340h
AN: SM23A-1180    [Abstracts]
TI: Investigation on Pi1 B pulsations using THEMIS ground-based magnetometers
AU: * Ge, Y
EM: ysge@ucal.edu
AF: IGPP UCLA, IGPP, UCLA 405 Hilgard Ave., LOS ANGELES, CA 90034, United States
AU: Russell, C T
EM: ctrussel@igpp.ucla.edu
AF: IGPP UCLA, IGPP, UCLA 405 Hilgard Ave., LOS ANGELES, CA 90034, United States
AU: Hsu, T
EM: thsu@igpp.ucla.edu
AF: IGPP UCLA, IGPP, UCLA 405 Hilgard Ave., LOS ANGELES, CA 90034, United States
AU: Mende, S
EM: mende@ssl.berkeley.edu
AF: Space Science Laboratory, Space Science Laboratory, University of California Berkeley, Berkeley, CA 94720, United States
AU: Angelopoulos, V
EM: vassilis@ucla.edu
AF: IGPP UCLA, IGPP, UCLA 405 Hilgard Ave., LOS ANGELES, CA 90034, United States
AU: Rae, J I
EM: jrae@Phys.UAlberta.CA
AF: Department of Physics, Department of Physics, University of Alberta, Edmonton, T6G 2J7, Canada
AU: McPherron, R L
EM: rmcpherron@igpp.ucla.edu
AF: IGPP UCLA, IGPP, UCLA 405 Hilgard Ave., LOS ANGELES, CA 90034, United States
AB: Pi1 B pulsations are believed associated with substorm onset. Because of the higher frequencies, 25 mHz to 1 Hz, Pi1 B has the potential to be a more accurate indicator of the time of substorm onset than Pi 2 pulsation. Thus it is important to understand the generation mechanism of Pi1 B and the relation between Pi1 B pulsations and substorm onset. However, observations of Pi1 B pulsations are not as easy as those of Pi 2 pulsations because of both smaller areas of Pi1 B occurrence and the limited availability of high-resolution magnetometer data on the ground. The THEMIS ground-based magnetometer network records magnetic field data with 0.5 second resolution and covers the full longitude of North American part of the auroral zone and sub-auroral region. We will examine the occurrence of Pi1 B pulsations using THEMIS ground magnetometer data to understand the local time and latitudinal distributions of Pi1 B. We will use the T.-S. Hsu's substorm event list which is identified by AL and Pi2 to examine the relation of Pi1 B and substorm onset.
DE: 2407 Auroral ionosphere (2704)
DE: 2721 Field-aligned currents and current systems (2409)
DE: 2736 Magnetosphere/ionosphere interactions (2431)
DE: 2752 MHD waves and instabilities (2149, 6050, 7836)
DE: 2790 Substorms
SC: SPA-Magnetospheric Physics [SM]
MN: 2007 Fall Meeting