Fast Time-Resolved Spectra of Electrostatic Turbulence in the Earth's Bow Shock

Abstract

We present time-resolved spectra of electrostatic turbulence in the earth's bow-shock structure. Spectral details on scales for a few Debye lengths indicate that single modes or groups of single modes dominate the turbulent spectrum. These modes are probably ion-acoustic or Buneman instabilities of short wavelength ($k{\lambda }_{\mathrm{D}}\sim 1$) which are generated in parts of the shock microstructure containing diamagnetic drift currents.