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Floating surface potential of spherical dust grains in magnetized plasmas

Published online by Cambridge University Press:  07 January 2016

Dennie Lange
Dennie Lange*
Affiliation:
Theoretische Physik I, Ruhr-Universität Bochum, Universitätsstr. 150, D-44780 Bochum, Germany
*
†Email address for correspondence: [email protected]
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Abstract

A particle-in-cell (PIC) simulation study of the charging processes of spherical dust grains in a magnetized plasma environment is presented. Different magnetic field strengths with corresponding electron/ion gyration radii of smaller, the same or larger size than the grain radius and the plasma Debye length are examined. The magnetized plasma is created by overlapping the simulation box with a homogeneous, constant magnetic field. The charging currents are significantly reduced in the presence of a magnetic field, resulting in a more negative grain floating potential. Indeed, the most probable electron gyration radius is always smaller than that of ions in a Maxwellian plasma: however, it is demonstrated that the situation of simultaneous magnetized electron but an unmagnetized ion charging current never exists. The simulation results do not fit with a modified orbital motion limited (OML) theory approach for this situation, since the ion current is significantly reduced due to the increase of the gyration radius in the potential field of the dust grain. For very small gyration radii, the simulation results are in good agreement with a modified OML approach for both magnetized electron and ion charging currents.

Type
Research Article
Information
Journal of Plasma Physics , Volume 82 , Issue 1 , February 2016 , 905820101
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Copyright
© Cambridge University Press 2016 

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