Generation of Alfvén waves by high power pulse at the electron plasma frequency

Abstract

The interaction of a short high power pulse at the electron plasma frequency (f = 9 GHz, τ = .5μs, P < 70 kW) and a magnetized plasma (n0 ≤ 1.25 · 1012 cm-3, B0 = 1.0 - 2.5 kG, Helium) capable of supporting Alfvén waves has been studied. The interaction leads to the generation of inertial shear Alfvén waves. The Alfvén waves are centered in an azimuthal layer corresponding to the location of the plasma frequency cutoff. The Alfvén waves are monochromatic with frequency within 10% of the ion cyclotron frequency. Spatial patterns of the wave were measured at different axial and radial locations. Copyright 2005 by the American Geophysical Union.