Abstract:
The effect of excess superthermal electrons is investigated on finite amplitude nonlinear ionacoustic
waves in a magnetized auroral plasma. The plasma model consists of a cold ion fluid,
Boltzmann distribution of cool electrons, and kappa distributed hot electron species. The model
predicts the evolution of negative potential solitons and supersolitons at subsonic Mach numbers
region, whereas, in the case of Cairn’s nonthermal distribution model for the hot electron species
studied earlier, they can exist both in the subsonic and supersonic Mach number regimes. For the
dayside auroral parameters, the model generates the super-acoustic electric field amplitude, speed,
width, and pulse duration of about 18 mV/m, 25.4 km/s, 663 m, and 26 ms, respectively, which is in
the range of the Viking spacecraft measurements.
