On the role of dust in the cometary plasma
B. A.Klumov, S. V. Vladimirov*, G. E. Morfill
Max-Planck-Institut für Extraterrestrische Physik, D-85740 Garching, Germany
*School of Physics, The University of Sydney, New South Wales 2006, Australia
PACS: 94.05.-a, 96.25.-y
Abstract
The cometary coma consists of neutral gas, plasma, and dust grains.
Dust grains can influence both the neutral and charged coma's constituents.
Usually, presence of dust particles in a plasma results in additional losses
of both electrons and ions due to the plasma recombination on the particle
surfaces. Solar radiation makes the impact of dust even more complicated,
depending on the solar flux, the dust number density, photoelectric
properties of the dust particles, the dust particle composition, distribution
of sizes, etc. We propose a simple kinetic model evaluating the role of dust
particles in the coma plasma chemistry and demonstrate that this role can be
crucial resulting in a nontrivial behavior of both the electron and ion
densities of the plasma. We show that coma's dust particles can be negatively
as well as positively charged depending on their composition. These opposite
charges of the grains can result in fast coagulation of dust particles
forming complex aggregate shapes of cometary grains.