HR: 1330h
AN: SM42C-0621    [PDF]
TI: Characteristics of Non-ducted Whistler-Induced Electron Precipitation
AU: * Peter, W B
EM: wpeter@stanford.edu
AF: Space, Telecommunications, and Radioscience Laboratory, Stanford University, 350 Serra Mall, Stanford, CA 94305 United States
AU: Inan, U S
EM: inan@nova.stanford.edu
AF: Space, Telecommunications, and Radioscience Laboratory, Stanford University, 350 Serra Mall, Stanford, CA 94305 United States
AB: We examine two different four-hour sequences of subionospheric Very Low Frequency (VLF) signal perturbations and provide a characterization of electron precipitation induced by non-ducted obliquely propagating whistlers. These lightning-induced electron precipitation (LEP) events are typically associated with cloud-to-ground lightning, with the event magnitudes positively correlated with the magnitude of the peak current of the discharge. A distributed set of VLF observing sites, known as the Holographic Array for Ionospheric and Lightning Research (HAIL), captures the full latitudinal extent of the events, providing evidence that 90% of the precipitation occurs within a range of $\sim 6-8\deg$ in latitude ($666-888$km). We further demonstrate that the onset delay ($\sim 0.5-3$s) and the duration of precipitation ($\sim1-4$s) steadily increase with increasing \emph{L}$-$value, while the signal recovery time ($\sim 30-40$s) is independent of \emph{L}. The dependence of the spatial and temporal parameters of the precipitation on the location of the causative lightning discharges is also examined. When the causative discharge is at higher latitudes, the LEP event is of longer duration and exhibits precipitation in a smaller area displaced less from the causative discharge. The onset delays and event durations increase more rapidly with increasing \emph{L}$-$value for events associated with causative discharges at higher latitudes. The general spatial and temporal signatures are consistent with those expected for LEP events induced by nonducted whistlers.
UR: http://www-star.stanford.edu/~hail/
DE: 2431 Ionosphere/magnetosphere interactions (2736)
DE: 2443 Midlatitude ionosphere
DE: 2455 Particle precipitation
DE: 2483 Wave/particle interactions
DE: 2716 Energetic particles, precipitating
SC: SPA - Magnetospheric Physics [SM]
MN: 2003 Fall Meeting