ON THE GENERATION OF PLASMA-WAVES IN SATURNS INNER MAGNETOSPHERE

Voyager 1 plasma wave measurements of Saturn's inner magnetosphere are reviewed with regard to interpretative aspects of the wave spectrum. A comparison of the wave emission profile with the electron plasma fre quency obtained from in situ measurements of the thermal ion density s hows good agreement with various features in the wave data identified as electrostatic modes and electromagnetic radio waves. Theoretical ca lculations of the critical flux of super-thermal electrons able to gen erate whistler-mode waves and electrostatic electron cyclotron harmoni c waves through a loss-cone instability are presented. The comparison of model results with electron measurements shows excellent agreement lending support to the conclusion that a moderate perpendicular anisot ropy in the hot electron distribution is present in the equatorial reg ion of L = 5-8.