Thermal creep assisted dust lifting on Mars: Wind tunnel experiments for the entrainment threshold velocity

Markus Küpper, Gerhard Wurm
(Submitted on 5 Aug 2015)

In this work we present laboratory measurements on the reduction of the threshold friction velocity necessary for lifting dust if the dust bed is illuminated. Insolation of a porous soil establishes a temperature gradient. At low ambient pressure this gradient leads to thermal creep gas flow within the soil. This flow leads to a sub-surface overpressure which supports lift imposed by wind. The wind tunnel was run with Mojave Mars Simulant and air at 3, 6 and 9 mbar, to cover most of the pressure range at martian surface levels. Our first measurements imply that the insolation of the martian surface can reduce the entrainment threshold velocity between 4 % and 19 % for the conditions sampled with our experiments. An insolation activated soil might therefore provide additional support for aeolian particle transport at low wind speeds.

Comments: accepted by JGR:Planets, 12 pages, 7 figures, 3 tables
Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
DOI: 10.1002/2015JE004848
Cite as: arXiv:1508.01047 [astro-ph.EP] (or arXiv:1508.01047v1 [astro-ph.EP] for this version)
Submission history
From: Markus Küpper
[v1] Wed, 5 Aug 2015 12:22:51 GMT (1283kb)
http://arxiv.org/abs/1508.01047