Journal of Plasma Physics

Letter to the Editor

Generation of magnetic fields in a positive–negative dusty plasma

NITIN SHUKLAa1a2, P.K. SHUKLAa1a3a4a5a6a7, C.S. LIUa1a8 and G.E. MORFILLa1a9

a1 Institut für Theoretische Physik IV and Centre for Plasma Science and Astrophysics, Fakultät für Physik und Astronomie, Ruhr-Universität Bochum, D-44780 Bochum, Germany (ns@tp4.rub.de; ps@tp4.rub.de)

a2 Department of Physics, K. N. Government Postgraduate College, Gyanpur, Bhadohi 221304, U. P., India

a3 Max-Planck Institut für extraterrestrische Physik, D-45741 Garching, Germany

a4 Centre for Nonlinear Physics, Department of Physics, Umeå University, SE-90187 Umeå, Sweden

a5 CCLRC Centre for Fundamental Physics, Rutherford Appleton Laboratory, Chilton, Didcot, Oxon OX11 OQX, UK

a6 SUPA Department of Physics, University of Strathclyde, Glasgow G4 ONG, UK

a7 GoLP/Centro de Física de Plasmas, Instituto Superior Técnico, Universidade Técnica de Lisboa, 1049-001 Lisboa, Portugal

a8 Department of Physics, University of Maryland, College Park, Maryland, MD 20742-4111, USA (csliu@umd.edu)

a9 Max-Planck Institut für extraterrestrische Physik, D-85740 Garching, Germany (gem@mpg.mpe.de)

Abstract.

It is shown that purely growing magnetic fields in a two-component dusty plasma can e generated due to the equilibrium drift of positive and negative dust grains. For this purpose, a linear dispersion relation has been derived by using the hydrodynamic equations for the charged dust fluids, the Maxwell equation and Faraday' law. The dispersion relation admits a purely growing instability, the growth rate of which is proportional to the equilibrium streaming speeds of positive and negative dust grains. A possible physical explanation for the instability is offered. Applications of our investigation to magnetic fields in the thin Martian environments, interplanetary spaces and dense molecular clouds are mentioned.

(Received September 26 2006)

(Accepted September 29 2006)