HR: 0830h
AN: SM31B-1115    [PDF]
TI: Measurements of the Geomagnetic Cutoff Rigidity-Dependence for Solar Energetic Particle Events
AU: * Labrador, A W
EM: labrador@srl.caltech.edu
AF: California Institute of Technology, MC 220-47, Pasadena, CA 91125 United States
AU: Leske, R
AF: California Institute of Technology, MC 220-47, Pasadena, CA 91125 United States
AU: Kanekal, S
AF: University of Maryland, Department of Physics, College Park, MD 20742 United States
AU: Klecker, B
AF: Max Planck Institut, feur Extraterrestrische Physik, Garching Bei Munchen, CA D-85741 Germany
AU: Looper, M
AF: The Aerospace Corp., P.O. Box 92957, M/S M2/260, Los Angeles, CA 90009 United States
AU: Mewaldt, R
AF: California Institute of Technology, MC 220-47, Pasadena, CA 91125 United States
AB: During large solar energetic particle (SEP) events, charged particles can ionize the atmosphere and alter atmospheric chemistry. Geomagnetic cutoff latitudes bound the polar regions of the atmosphere exposed to solar particles. The size of the exposed polar regions may change significantly during SEP events, correlating well with geomagnetic activity. During SEP events, the geomagnetic cutoff latitude can vary by more than 10 degrees. Using data from the MAST instrument on SAMPEX, we have measured geomagnetic cutoffs for 17 large SEP events, including the 4/21/02 event. We will combine these measurements with data from other SAMPEX instruments to investigate how the size of the polar regions depends on particle rigidity, how this dependence may change with time during an event, and how the measurements compare with models.
DE: 0399 General or miscellaneous
DE: 2799 General or miscellaneous
DE: 7513 Coronal mass ejections
DE: 7514 Energetic particles (2114)
SC: SPA - Magnetospheric Physics [SM]
MN: 2003 Fall Meeting