Journal of Plasma Physics

Letter to the Editor

Particle acceleration by lower-hybrid turbulence

R. BINGHAM a1, J. M. DAWSON a1 1 2 and V. D. SHAPIRO a1 3
a1 Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX, UK (


We investigate particle acceleration by strong lower-hybrid turbulence produced by the relaxation of an energetic perpendicular ion ring distribution. Ion ring distributions are associated with counterstreaming plasma flows in a magnetic field, and are found at perpendicular shocks as a result of ion reflection from the shock surface. Using a 2½D particle-in-cell (PIC) code that is fully electromagnetic and relativistic, we show that the ion ring is unstable to the generation of strong plasma turbulence at the lower-hybrid resonant frequency. The lower-hybrid wave turbulence collapses in configuration space, producing density cavities. The collapse of the cavities is halted by particle acceleration, producing energetic electron and ion tails. For solar flare plasmas with temperatures of 1 keV and a ratio of the plasma frequency to the electron cyclotron frequency of ½, we demonstrate electron acceleration to energies up to MeV, while the ions are accelerated to energies in the region of several MeV.

(Received December 11 2001)


1 This paper was completed just before the unfortunate death of Professor John Dawson, whom we all miss dearly. Although he is gone, his spirit lives on, and this paper is dedicated to him and his life.

2 Department of Physics, University of California, Los Angeles, California 90024-1547, USA

3 Department of Physics, University of California, San Diego, La Jolla, CA 92093-0319, USA