DISCRETE, STIMULATED AURORAL KILOMETRIC RADIATION OBSERVED IN THE GALILEO AND DE-1 WIDE-BAND DATA

The Galileo spacecraft observed intense auroral kilometric radiation d uring the second Earth encounter in 1992. High-resolution frequency-ve rsus-time spectrograms obtained by the wideband receiver of the plasma wave instrument on board the spacecraft often show discrete, negative -slope features each extending over a period of several seconds. These features may be due to impulsive wave generation and intrinsic veloci ty dispersion and/or a source stimulation by plasma waves traveling up the magnetic field line through the source region. We present several examples of these signatures, seen also on the Dynamics Explorer 1 sa tellite, and examine scenarios for their generation.