HR: 14:25h
AN: AE13A-04    [Abstracts]
TI: ELF/VLF radio from runaway breakdown and cosmic ray air showers
AU: * Fullekrug, M
EM: eesmf@bath.ac.uk
AF: Martin Fullekrug, University of Bath, Bath, BA2 7AY United Kingdom
AU: Roussel-Dupre, R
AE13A-04 AF: Robert Roussel-Dupre, Los Alamos National Laboratory, Los Alamos, 87545 United States
AU: Rodger, C J
AE13A-04 AF: Craig J. Rodger, University of Otago, Dunedin, 000 New Zealand
AU: Falcke, H
AE13A-04 AF: Heino Falcke, Radboud University, Nijmegen, 6500 Netherlands
AU: Huege, T
AE13A-04 AF: Tim Huege, Forschungszentrum Karlsruhe, Karlsruhe, 76021 Germany
AB: The natural electromagnetic environment at low radio frequencies from 10 Hz to 30 kHz (ELF/VLF) is dominated by impulsive bursts from lightning discharges in the troposphere. Particularly intense positive lightning discharges can cause transient luminous events (TLEs) in the mesosphere, denoted sprites, which mainly result from the quasi-static heating of the neutral gas in the mesosphere. The most spectacular 20 % of sprites produce radio signals at extremely-low frequencies from 10 Hz to 3 kHz (ELF), which are currently believed to result mainly from conventional mesospheric breakdown. Alternatively, the observed radio signals may be dominated by relativistic runaway breakdown in the mesosphere. The respective current source functions of conventional and relativistic breakdown are connected to an ELF/VLF propagation model to calculate the electromagnetic fields of both physical processes at a distance and to determine the most appropriate method to discriminate between the two different physical processes. Extensive cosmic ray air showers from ultra-high energy extra-galactic cosmic rays >100 EeV similarly produce radio signals up to the high frequency range from 3-300 MHz (HF/VHF). The ELF/VLF radio signals from this cosmic ray current source function is calculated by using the same ELF/VLF propagation model. The prospects for the detection of the radio signals from relativistic runaway breakdown and cosmic rays are discussed in the light of reported instrumental sensitivities.
DE: 1530 Rapid time variations
DE: 6914 Electromagnetic noise and interference
SC: Atmospheric and Space Electricity [AE]
MN: Fall Meeting 2005