Observations of VLF Chorus in the Aftermath of Large Geomagnetic Storms

In the aftermath of large geomagnetic storms, the plasmasphere is eroded to low L-shells and the flux of ring current electrons (10-100 keV) is substantially elevated. These conditions are conducive to the generation of intense whistler mode chorus emissions in the inner magnetosphere. There is increasing evidence that resonant interactions between chorus and energetic electrons can result in the acceleration of these electrons up to relativistic energies. We will present observations of broadband VLF wave activity from ground stations located at L=2.5 (Palmer Station, Antarctica) and L=5.1 (Chistochina, Alaska) during several of the geomagnetic superstorms of the past few years including the most recent January 2005 events and the Halloween 2003 event. We will explore the relationship between chorus wave intensity and duration to global enhancements in the radiation belts.