Acceleration of a Plasma Flow by Oscillating Magnetic Mirrors
Conference Paper
Overview
Identity
Other
View All
Overview
abstract
This paper explores the phenomenon of Fermi acceleration for possible application to plasma propulsion devices. The Lattice-Boltzmann Method based upon magnetohydrodynamics simulates plasma response to an externally applied magnetic field. The applied field configured as a magnetic bottle traps plasma injected into it by a rectangular jet. Moving the mirrors toward each other contracts the bottle and accelerates the plasma. Plasma loss associated with the magnetic bottle is a desired side effect constituting the propulsive mechanism for the device. Different time-varying magnetic fields, injection velocities, and magnetic Reynolds numbers are simulated. Cases demonstrating high exit velocity in the axial direction and minimal reverse flow are examined. The best cases exhibit exit flow accelerated to approximately twice its injection velocity in the axial direction and three times the injection velocity in the lateral direction. A magnetic field generated by loops with sinusoidally-varying positions shows the best results, while that from linearly-varying positions that return to their original positions in one time step is the most likely implementation for a propulsion or flow control device. Proportionally increasing injection velocity and current loop frequency is found not to increase exit velocity. The paper concludes that Fermi acceleration would be better used as a propulsion supplement and not as a stand-alone device. 2008 by the American Institute of Aeronautics and Astronautics, Inc.
