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Heating and ionization of the lower ionosphere by lightning
Author(s) -
Inan U. S.,
Bell T. F.,
Rodriguez J. V.
Publication year - 1991
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/91gl00364
Subject(s) - ionosphere , ionization , lightning (connector) , electron , altitude (triangle) , physics , atomic physics , radiation , atmospheric sciences , ion , computational physics , geophysics , nuclear physics , power (physics) , geometry , mathematics , quantum mechanics
Nighttime ionospheric electrons at 90–95 km altitude are found to be heated by a factor of 100–500 during the upward passage of short (< 100 μs) pulses of intense (5–20 V/m at 100 km distance) electromagnetic radiation from lightning. Heated electrons with average energy of 4–20 eV in turn produce secondary ionization, of up to 400 cm −3 at ∼95 km altitude in a single ionization cycle (∼3 μs). With the time constant of heating being 5–10 μs, a number of such ionization cycles can occur during a 50 μs, radiation pulse, leading to even higher density enhancements. This effect can account for previously reported observations of ‘early’ or ‘fast’ subionospheric VLF perturbations.