HR: 1340h
AN: SM53A-1089    [Abstracts]
TI: On the Physics of the Interaction of a Rotating Magnetic Field with a Magnetized Plasma
AU: * Karavaev, A V
EM: a.v.karavaev@gmail.com
AF: Departments of Physics and Astronomy, University of Maryland, College Park, MD 20742, United States
AU: Papadopoulos, K
EM: dpapadop@umd.edu
AF: Departments of Physics and Astronomy, University of Maryland, College Park, MD 20742, United States
AU: Shao, X
EM: xshcn@astro.umd.edu
AF: Departments of Physics and Astronomy, University of Maryland, College Park, MD 20742, United States
AU: Milikh, G
EM: milikh@astro.umd.edu
AF: Departments of Physics and Astronomy, University of Maryland, College Park, MD 20742, United States
AU: Gekelman, W
EM: gekelman@physics.ucla.edu
AF: Department of Physics and Astronomy, University of California, Los Angeles, CA 90095, United States
AU: Gigliotti, A
EM: alexgig88@gmail.com
AF: Department of Physics and Astronomy, University of California, Los Angeles, CA 90095, United States
AU: Vincena, S
EM: vincena@physics.ucla.edu
AF: Department of Physics and Astronomy, University of California, Los Angeles, CA 90095, United States
AB: The interaction of Rotating Magnetic Fields (RMF) with plasmas is a fundamental plasma physics problem with implications to fusion related Field-Reversed Configurations (FRC), space propulsion, astronaut protection from cosmic rays in long interstellar travel, control of energetic population in the radiation belts and near zone processes in pulsar magnetospheres. An important but not yet explored application of RMF is as an efficient radiation source of MHD and whistler waves in space plasmas. Despite its importance the basic plasma physics understanding of the interaction of rotating magnetic fields with magneto-plasmas, the scaling laws that control it and the range of potential applications to space plasmas remains unexplored. To zero order a magnetic field rotating at a rate w in a plasma drives plasma currents due to the difference in mass between electrons and ions. The electrons quickly come to a co-rotation with RMF, generating a differential azimuthal current whose maximum is given by Jtheta = nwr . The RMF can be generated either by a pair of polyphase coils, superconducting or else, or a rotating permanent magnet. Key questions include the depth of penetration of the field in the plasma, the spatiotemporal structure of the induced magnetic field as a function of the RMF and plasma parameters and the spatial decay rate magnetic field. Flux conservation arguments indicate that the induced field will decay slower than 1/r**2 and 2D simulation studies indicate that depending on the plasma beta it falls as 1/r**n with n smaller than 1.5. Our preliminary simulations indicate that penetration lengths exceeding 20-30 collisionless skin depths can be reached. The paper will present a combination of analytic/computational results along with preliminary experiments conducted using the Large Plasma Device (LAPD) located at UCLA that emphasize the RMF properties for generating MHD and whistler waves. This work was sponsored by ONR MURI Grant 5-28828
DE: 2483 Wave/particle interactions (7867)
DE: 2487 Wave propagation (0689, 3285, 4275, 4455, 6934)
DE: 2794 Instruments and techniques
SC: SPA-Magnetospheric Physics [SM]
MN: 2007 Fall Meeting