The role of nonlinear interaction in the formation of LF whistler turbulence upstream of a quasi-perpendicular shock

摘要

The role of the nonlinear interaction in developed low-frequency turbulence has been experimentally studies upstream of the ramp of a quasiperpendicular shock. The study has been carried out by application of the methods of bispectral analysis and wavelet decomposition to the Active Magnetospheric Particle Tracer Explorer Ion Release Module and Interball Tail Probe magnetic field data. It is shown that three-wave processes play a key role in the formation of the spectrum of the turbulence. Experimental results presented and previous theoretical consid-erations lead to the conclusion that energy is transferred from a narrow maximum frequency pumped by nonlinear dynamic processes to lower and higher frequencies.