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is the electron avalanche process in a martian dust devil self-quenching?Viking era laboratory experiments show that mixing tribocharged grains in a low pressure CO2 gas can form a discharge that glows, indicating the presence of an excited electron population that persists over many seconds. Based on these early experiments, it has been predicted that martian dust devils and storms may also contain a plasma and new plasma chemical species as a result of dust grain tribo-charging. However, recent results from modeling suggest a contrasting result: that a sustained electron discharge may not be easily established since the increase in gas conductivity would act to short-out the local E-fields and quickly dissipate the charged grains driving the process. In essence, the system was thought to be self-quenching (i.e., turn itself off). In this work, we attempt to reconcile the difference between observation and model via new laboratory measurements. We conclude that in a Mars-like low pressure CO2 atmosphere and expected E-fields, the electron current remains (for the most part) below the expected driving tribo-electric dust currents (approx. 10 microA/m(exp. 2)), thereby making quenching unlikely.
Document ID
20160005755
Document Type
Reprint (Version printed in journal)
Authors
Farrell, William M.
(NASA Goddard Space Flight Center Greenbelt, MD United States)
McLain, Jason L.
(Maryland Univ. College Park, MD, United States)
Collier, M. R.
(NASA Goddard Space Flight Center Greenbelt, MD United States)
Keller, J. W.
(NASA Goddard Space Flight Center Greenbelt, MD United States)
Jackson, T. J.
(NASA Goddard Space Flight Center Greenbelt, MD United States)
Delory, G. T.
(California Univ. Berkeley, CA, United States)
Date Acquired
May 3, 2016
Publication Date
April 11, 2015
Publication Information
Publication: Icarus
Volume: 254
ISSN: 0019-1035
Subject Category
Space Sciences (General)
Lunar and Planetary Science and Exploration
Report/Patent Number
GSFC-E-DAA-TN31396
Funding Number(s)
CONTRACT_GRANT: NNG06EO90A
Distribution Limits
Public
Copyright
Other
Keywords
Electron
Meteorology
Mars