Journal of Plasma Physics

Papers

Lower-hybrid waves generated by anomalous Doppler resonance in auroral plasmas

R. BINGHAMa1a2, R. A. CAIRNSa2, I. VORGULa2 and V. D. SHAPIROa3

a1 Rutherford Appleton Laboratory, Chilton, Oxon, OX11 0QX, UK (bob.bingham@stfc.ac.uk)

a2 Department of School of Mathematics and Statistics, University of St Andrews, St Andrews, Fife, Scotland, KY16 9SS

a3 Department of Physics, University of California, San Diego, La Jolla, CA 92091, USA

Abstract

This paper describes some aspects of lower-hybrid wave activity in space plasmas. Lower-hybrid waves are particularly important since they can transfer energy efficiently between electrons and ions in a collisionless magnetized plasma. We consider the ‘fan’ or anomalous Doppler resonance instability driven by energetic electron tails and show that it is responsible for the generation of lower-hybrid waves. We also demonstrate that observations of their intensity are sufficient to drive the modulational instability.

(Received December 04 2009)

(Accepted December 13 2009)

(Online publication January 21 2010)