Precipitation of Energetic Electrons by Magnetospherically Reflecting (MR) Whistlers

Long enduring (~10 s or more) precipitation of energetic electrons by magnetospherically reflected (MR) whistler episodes excited by individual lightning flashes have recently been reported in the form of drift-loss-cone enhancements observed on the SAMPEX satellite [Blake et al., 2001] and direct observations in the bounce-loss-cone via the associated subionospheric VLF signatures [Inan et al., 2003]. These observations indicate that the effect on the radiation belt electrons of electromagnetic energy injected by lightning may be more significant than previously believed, since each lightning may continue to drain the belts for tens of seconds as the MR whistler energy propagates back and forth between hemispheres. In this paper, we report on the results of a statistical analysis of MR whistler-induced precipitation events as observed with the Holographic Array for Lightning (HAIL), consisting of multiple observing stations configured in a north-south orientation in the mid-western United States. MR whistler-induced episodes are recognized in HAIL data in view of the long onset delays (many seconds) and event durations (many seconds).