Open AccessConnecting the terrestrial gamma‐ray flash source strength and observed fluence distributions
Author(s) -
Carlson B. E.,
Gjesteland T.,
Østgaard N.
Publication year - 2012
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2011ja017122
Subject(s) - gamma ray , flash (photography) , fluence , geology , materials science , physics , astrophysics , optics , nuclear physics , irradiation
Terrestrial gamma‐ray flashes (TGFs) as observed by satellites have a broad fluence distribution. This fluence distribution is not trivially related to the source strength distribution, since even a very strong TGF may still be observed at low fluence if the source is far from the satellite. In this paper we connect the source strength distribution with the observed fluence distribution by calculating the effective size and probability of detection of TGFs as a function of their source strength. For sources at a single altitude, power law distributions of source strength give softer power law distributions in observed fluence with especially pronounced softening for very hard source power law indices. This result holds even with broad source altitude distributions in regions of the fluence distribution away from the peak fluence since such regions tend to be dominated by TGFs produced in a relatively narrow range of higher altitudes.