HR: 09:00h
AN: SM41A-04 INVITED     [PDF]
TI: Magnetospheric and Auroral Activity during Sawtooth Events: Energy Flow Through the MIA system During Periodic Magnetospheric Disturbances
AU: * Henderson, M G
EM: mghenderson@lanl.gov
AF: Los Alamos National Laboratory, MS D466, Los Alamos, NM 87545 United States
AU: Skoug, R
EM: rskoug@lanl.gov
AF: Los Alamos National Laboratory, MS D466, Los Alamos, NM 87545 United States
AU: Thomsen, M F
EM: mthomsen@lanl.gov
AF: Los Alamos National Laboratory, MS D466, Los Alamos, NM 87545 United States
AU: Borovsky, J
EM: jborovsky.lanl.gov
AF: Los Alamos National Laboratory, MS D466, Los Alamos, NM 87545 United States
AU: Reeves, G D
EM: reeves@lanl.gov
AF: Los Alamos National Laboratory, MS D466, Los Alamos, NM 87545 United States
AU: Immel, T J
EM: immel@ssl.berkeley.edu
AF: Space Sciences Laboratory, University of California, Berkeley, CA 94720-7450
AU: Mende, S B
EM: mende@ssl.berkeley.edu
AF: Space Sciences Laboratory, University of California, Berkeley, CA 94720-7450
AU: Lui, A T
EM: Tony.Lui@jhuapl.edu
AF: Johns Hopkins University Applied Physics Laboratory, 11100 JOHNS HOPKINS RD, Laurel, MD 20723-6099 United States
AB: During intervals of prolonged moderate but steady southward IMF Bz, the magnetosphere frequently enters a state in which quasi-periodic, large-amplitude, global oscillations are observed in the geosynchronous energetic particle fluxes. These oscillations have been termed ``sawtooth events" because their shape -- a series of slow flux decreases followed by rapid increases -- resemble the teeth of a saw blade. Recent studies of sawtooth events have shown that each of the flux increases are associated with characteristic substorm onset signatures including field dipolarization, injection of energetic particles, ground magnetic perturbations, and embedded auroral onsets. Thus, it has been shown that sawtooth events are actually a sequence of recurrent quasi-periodic substorms. In addition, the level of solar wind driving necessary to induce sawtooth behavior appears to be transitional between driving levels that give rise to SMC (steady magnetospheric convection) and full-blown storm type behavior. Sawtooth events can therefore be viewed as a magnetospheric mode similar to SMCs except that for sawtooth events, the flow of energy from the solar wind into the magnetosphere becomes too large to dissipate without the (literally) periodic occurrence of substorms. I.e., the magnetosphere is continuously ``driven'' toward substorm-like reconfigurations in order to ``reset'' itself at periodic intervals. In this presentation we examine the possibility that during such long-lived, predominantly driven events, the energy input to the ionosphere/atmosphere system is greatly enhanced by the continuously driven auroral disturbances that occur.
DE: 2704 Auroral phenomena (2407)
DE: 2720 Energetic particles, trapped
DE: 2730 Magnetosphere--inner
DE: 2788 Storms and substorms
SC: SPA - Magnetospheric Physics [SM]
MN: 2003 Fall Meeting