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Effect of dust absorption on the electron avalanche process occurring within Martian dust storms
Author(s) -
Jackson Telana L.,
Farrell William M.,
Delory Greg T.,
Nithianandam Jeyasingh
Publication year - 2008
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 - 10.1029/2008gl034523
Subject(s) - martian , electron avalanche , electron , ionization , atomic physics , atmosphere of mars , absorption (acoustics) , atmospheric sciences , physics , electric field , townsend discharge , materials science , environmental science , mars exploration program , astrobiology , optics , ion , quantum mechanics
Martian dust devils and storms are believed to generate and maintain large‐scale E‐fields which may be strong enough to create a weakly ionized plasma in the low pressure CO 2 atmosphere. Previous studies of the electron development included a determination of the avalanching electron growth via electron impact ionization with CO 2 at electron energy levels above 14 eV. Townsend's first coefficient defining the path length for impact ionization was calculated as a function of driving electric field. Such calculations demonstrated the growth of the electron avalanche but did not include any electron loss processes. Herein, we consider the effect of such a loss process: electron absorption by dust grains. The inclusion of electron‐dust absorption has a moderating effect, controlling electron avalanche growth. A critical E‐field to initiate the avalanche is derivable, with fields below ∼7 kV/m quenching the process but above 7 kV/m fully capable of stimulating electron growth in the storm.