Laboratory simulation of broadband ELF waves in the auroral ionosphere

Space-relevant observational signatures, such as frequency spectra, phase v elocities, excitation thresholds, and ion heating, associated with electros tatic ion-cyclotron waves excited by the inhomogeneous energy-density drive n (IEDD) instability in a laboratory experiment are presented. A comparison is made between these waves and the broadband ELF waves recently observed in the auroral ionosphere with sounding rockets and satellites. The measure ments of broadband spectra, electron-landau-resonant phase velocities, low excitation threshold value of parallel electron drift speed, and significan t perpendicular ion heating suggest that attributing the broadband ELF wave s to the IEDD instability mechanism is justified.