Oxidant enhancement in martian dust devils and storms: storm electric fields and electron dissociative attachment.

Published

Journal Article (Review)

Laboratory studies, numerical 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 and dust storms, grain stratification leads to macroscopic charge separations and gives rise to an overall electric dipole moment in the aeolian feature, similar in nature to the dipolar electric field generated in terrestrial thunderstorms. Previous numerical simulations indicate that these storm electric fields on Mars can approach the ambient breakdown field strength of approximately 25 kV/m. In terrestrial dust phenomena, potentials ranging from approximately 20 to 160 kV/m have been directly measured. The large electrostatic fields predicted in martian dust devils and storms can energize electrons in the low pressure martian atmosphere to values exceeding the electron dissociative attachment energy of both CO2 and H2O, which results in the formation of the new chemical products CO/O- and OH/H-, respectively. Using a collisional plasma physics model, we present calculations 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 the breakdown value of approximately 25 kV/m. The dissociation of H2O into OH/H- provides a key ingredient for the generation of oxidants; thus electrically charged dust may significantly impact the habitability of Mars.

Full Text

Duke Authors

Cited Authors

  • Delory, GT; Farrell, WM; Atreya, SK; Renno, NO; Wong, A-S; Cummer, SA; Sentman, DD; Marshall, JR; Rafkin, SCR; Catling, DC

Published Date

  • June 2006

Published In

Volume / Issue

  • 6 / 3

Start / End Page

  • 451 - 462

PubMed ID

  • 16805701

Pubmed Central ID

  • 16805701

Electronic International Standard Serial Number (EISSN)

  • 1557-8070

International Standard Serial Number (ISSN)

  • 1531-1074

Digital Object Identifier (DOI)

  • 10.1089/ast.2006.6.451

Language

  • eng