HR: 1340h
AN: SA13A-1122    [Abstracts]
TI: Oxidant Enhancement in Martian Dust Devils and Storms: I. Storm Electric Fields and Electron Dissociative Attachment
AU: * Delory, G T
EM: gdelory@ssl.berkeley.edu
AF: University of California, Space Sciences Laboratory, Berkeley, CA 94720 United States
AU: Farrell, W T
EM: farrell@faltraz.gsfc.nasa.gov
AF: NASA Goddard Space Flight Center, Laboratory for Extraterrestrial Physics, Greenbelt, MD 20771 United States
AU: Sentman, D D
EM: dsentman@gi.alaska.edu
AF: University of Alaska, Geophysical Institute, Fairbanks, AK 99775 United States
AU: Renno, N O
EM: nrenno@umich.edu
AF: University of Michigan, College of Engineering Atmospheric, Oceanic, and Space Sciences, Ann Arbor, MI 48109 United States
AU: Atreya, S K
EM: atreya@umich.edu
AF: University of Michigan, College of Engineering Atmospheric, Oceanic, and Space Sciences, Ann Arbor, MI 48109 United States
AU: Wong, A
EM: aswong@umich.edu
AF: University of Michigan, College of Engineering Atmospheric, Oceanic, and Space Sciences, Ann Arbor, MI 48109 United States
AU: Cummer, S A
EM: cummer@ee.duke.edu
AF: Duke University, Department of Electrical and Computer Engineering, Durham, NC 27708 United States
AU: Marshall, J
EM: jmarshall@seti.org
AF: SETI Institute, 2035 Landings Drive, Mountain View, CA 94043 United States
AU: Rafkin, S
EM: rafkin@boulder.swri.edu
AF: Southwest Research Institute, 1050 Walnut St., Suite 400, Boulder, CO 80302 United States
AU: Catling, D
EM: davidc@atmos.washington.edu
AF: University of Washington, Department of Atmospheric Sciences/Astrobiology Program, Seattle, WA 98105 United States
AB: Laboratory studies, computer simulations, and desert field tests indicate that aeolian dust transport can generate atmospheric electricity via contact electrification or "triboelectricity". In convective structures such as dust devils or storms, grain stratification (leading to charge separation) gives rise to an overall electric dipole moment to the aeolian feature, similar in nature to the dipolar electric field generated in terrestrial thunderstorms. Previous simulation studies indicate that this storm electric field on Mars can approach the ambient breakdown field strength of 20 kV/m. Noteable, in terrestrial dust devils, coherent dipolar electric fields have been measured to near 20 kV/m. Given the expected electrostatic fields in Martian dust devils and storms, electrons in the low pressure CO2 gas can be energized via electric fields to values exceeding the electron dissociative attachment energy of both CO2 and H2O, resulting in the formation of new chemical products CO and O- and OH and H- within the storm. Using a collisional plasma physics model, we present a calculation of the CO/O- and OH/H- reaction and production rates. We demonstrate that these rates vary geometrically with the ambient electric field, with substantial production of dissociative products when fields approach breakdown levels of 20-30 kV/m. These storm-related chemical products are key ingredients for the generation of oxidants which can ultimately affect the habitability of Mars, as discussed in the following companion presentation.
DE: 5704 Atmospheres--composition and chemistry
DE: 3346 Planetary meteorology (5445, 5739)
DE: 3304 Atmospheric electricity
DE: 0343 Planetary atmospheres (5405, 5407, 5409, 5704, 5705, 5707)
DE: 0614 Biological effects
SC: SPA-Aeronomy [SA]
MN: 2004 AGU Fall Meeting