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M. Makuch, N. V. Brilliantov, F. Spahn (University of Potsdam, Germany), A. V. Krivov (Friedrich Schiller University, Jena, Germany)
Dust tori around Mars were predicted theoretically several decades ago, but still escape direct detection. On the base of our recent analytical and numerical studies we re-assess expected properties of the dust belts. In addition to deterministic models developed before we investigate the influence of stochastic effects on the dynamics, lifetimes of particles, and configuration of the dust tori.
There exist various sources of stochasticity. For instance, we consider the influence of solar radiation on an ensemble of differently-shaped dust particles. Following the ergodic hypothesis, the dynamics of a single dust grain exposed to fluctuating radiation mimics the stochastic evolution of the whole ensemble. Further, we study the action of the planetary shadow on the dynamics of dust particles, a perturbation which turns out to be stochastic. Additional stochastic perturbations of deterministic dust trajectories are expected to be caused by different material properties of the dust grains, fluctuations of the solar wind, and the related magnetic field.
As a result the fluctuating forces cause a diffusion of the dust configuration whose related fluxes can be estimated from our numerical experiments. This effect leads to a decrease of the expected optical depth of the tori, which is mainly determined by the strength of the stochastic force. We will provide estimates for the latter resulting in a diffusion coefficient. This will give new information about change of the configuration and lifetimes of the Martian dust-tori.
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Bulletin of the American Astronomical Society, 37 #3
© 2004. The American Astronomical Soceity.