Cluster observations of shock-turbulence interactions

Abstract

Measurements of wave number spectra for two-dimensional, Alfvénic, and compressible fluctuations are presented in the solar wind and the regions related to the collisionless shocks. The spectra are determined from the four-point magnetometer data recorded by the Cluster spacecraft. The solar wind exhibits spectral curves characteristic of the inertial and the dissipation ranges of turbulence and appears to be dominated by two-dimensional turbulence. The fluctuations become more intense and the spectra are modified as the solar wind interacts with the bow shock, suggesting that the plasma instabilities are operating in the foreshock and the magnetosheath.