Three-dimensional electron magnetohydrodynamic reconnection. IV. Instabilities, fluctuations, and emissions

Further observations are presented on a reconnection experiment involving three-dimensional magnetic fields in the parameter regime of electron magnetohydrodynamics. The focus is on current-driven instabilities in the magnetic neutral sheet. Density fluctuations are observed in the neutral sheet and identified as current-driven ion sound turbulence. No lower hybrid turbulence or Buneman instabilities are detected. Enhanced thermal fluctuations are measured in the range of the electron plasma frequency. Microwave radiation is emitted from the plasma and explained by mode conversion of plasma waves on density gradients. The role of these instabilities in the conversion of magnetic energy and energy and transport is discussed. (C) 2003 American Institute of Physics.