Electrostatic discharge in Martian dust storms

Citation
O. Melnik et M. Parrot, Electrostatic discharge in Martian dust storms, J GEO R-S P, 103(A12), 1998, pp. 29107-29117
Citations number
45
Categorie Soggetti
Space Sciences
Journal title
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
ISSN journal
21699380 → ACNP
Volume
103
Issue
A12
Year of publication
1998
Pages
29107 - 29117
Database
ISI
SICI code
0148-0227(199812)103:A12<29107:EDIMDS>2.0.ZU;2-E
Abstract
Although the Martian atmosphere does not satisfy general requirements for l ightning generation, there is a possibility of electrical discharge in the case of strong surface winds and a resulting extremely large dust mass load ing in the course of large dust storms occurring on this planet. On Earth, negative potential gradients of many thousands of volts per meter have been measured during dust storms when winds are sufficiently strong. However, o wing to a lower pressure in the Martian atmosphere, the required voltage fo r electrical breakdown is lower than on Earth. After a brief review of the observations concerning Earth's atmosphere and the laboratory experiments p erformed to understand these phenomena, the results of numerical simulation of the electrification in Martian dust storms are presented. Known charact eristics of Martian dust grains and the Martian atmosphere are considered, and the different forces applied to the dust particles are taken into accou nt. The electrostatic potential and the evolution of the charge density are calculated using Poisson's equation and the continuity equation. Two diffe rent wind configurations in the Martian atmosphere are studied: a wind vort ex and a wind parallel to the ground encountering an obstacle (a small hill ). It is shown that electric discharge occurs under specific conditions.