Gyrokinetic modelling of the kinetic-ballooning instability in the magnetosphere

Tuesday, 16 December 2014
Nikolai Gorelenkov1, Peter Porazik2 and Jay Johnson2, (1)Princeton University, Princeton, NJ, United States, (2)Princeton Plasma Physics Lab, Princeton, NJ, United States
Recently, small scale azimuthal structuring in optical signatures associated with low frequency Pc1/2 wave activity has been observed around the time of substorm onset. The characteristic frequency and kinetic-scale structuring have been attributed to the onset of a kinetic ballooning instability, which can occur in high-beta magnetized plasmas in regions where the magnetic curvature and pressure gradient are in opposite directions. We present recent progress on electromagnetic gyrokinetic simulations of the ballooning instability in a realistic stretched dipole geometry to examine the properties of the instability and compare with optical and wave signatures observed at substorm onset.