Relativistic electron avalanches as a thunderstorm discharge competing with lightning.
Gamma-ray 'glows' are long duration (seconds to tens of minutes) X-ray and gamma-ray emission coming from thunderclouds. Measurements suggest the presence of relativistic runaway electron avalanches (RREA), the same process underlying terrestrial gamma-ray flashes. Here we demonstrate that glows are relatively a common phenomena near the tops of thunderstorms, when compared with events such as terrestrial gamma-ray flashes. Examining the strongest glow measured by the airborne detector for energetic emissions, we show that this glow is measured near the end of a downward RREA, consistent with occurring between the upper positive charge layer and the negative screening layer above it. The glow discharges the upper positive layer by ≥9.6 mA, strong enough to be an important charging mechanism of the storm. For this glow, the gamma-ray flux observed is close to the value at which relativistic feedback processes become important, with an avalanche multiplication factor of 4,500.
Space Sciences Laboratory, University of California, Berkeley, 7 Gauss Way, Berkeley, California 94705, USA.
Nicole A
NA
Kelley
Physics Department and Santa Cruz Institute for Particle Physics, University of California, 1156 High Street, Santa Cruz, California 95064, USA.
David M
DM
Smith
Department of Physics, University of New Hampshire, 8 College Road, Durham, New Hampshire 03824, USA.
Joseph R
JR
Dwyer
Department of Marine and Environmental Systems, Florida Institute of Technology, 150 West University Boulevard, Melbourne, Florida 32901, USA.
Michael
M
Splitt
Department of Marine and Environmental Systems, Florida Institute of Technology, 150 West University Boulevard, Melbourne, Florida 32901, USA.
Steven
S
Lazarus
Physics Department and Santa Cruz Institute for Particle Physics, University of California, 1156 High Street, Santa Cruz, California 95064, USA.
Forest
F
Martinez-McKinney
Physics Department, University of Washington, 3910 15th Avenue North East, Seattle, Washington 98195, USA.
Bryna
B
Hazelton
Space Radiation Laboratory, California Institute of Technology, 290-17 Cahill, 1200 East California Boulevard, Pasadena, California 91125, USA.
Brian
B
Grefenstette
Space Sciences Laboratory, University of California, Berkeley, 7 Gauss Way, Berkeley, California 94705, USA.
Alexander
A
Lowell
Department of Physics and Space Sciences, Florida Institute of Technology, 150 West University Boulevard, Melbourne, Florida 32901, USA.
Hamid K
HK
Rassoul