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We present the first quantified measure of the rate of energy dissipated perunit volume by high frequency electromagnetic waves in the transition region ofthe Earth's collisionless bow shock using data from the THEMIS spacecraft.Every THEMIS shock crossing examined with available wave burst data showed bothlow frequency (< 10 Hz) magnetosonic-whistler waves and high frequency (> 10Hz) electromagnetic and electrostatic waves throughout the entire transitionregion and into the magnetosheath. The waves in both frequency ranges had largeamplitudes, but the higher frequency waves, which are the focus of this study,showed larger contributions to both the Poynting flux and the energydissipation rates. The higher frequency waves were identified as combinationsof ion-acoustic waves, electron cyclotron drift instability driven waves,electrostatic solitary waves, and whistler mode waves. These waves were foundto have: (1) amplitudes capable of exceeding dB ~ 10 nT and dE ~ 300 mV/m,though more typical values were dB ~ 0.1-1.0 nT and dE ~ 10-50 mV/m; (2) energyfluxes in excess of 2000 x 10^(-6) W m^(-2); (3) resistivities > 9000 Ohm m;and (4) energy dissipation rates > 3 x 10^(-6) W m^(-3). The dissipation rateswere found to be in excess of four orders of magnitude greater than wasnecessary to explain the increase in entropy across the shocks. Thus, the wavesneed only be, at times, < 0.01% efficient to balance the nonlinear wavesteepening that produces the shocks. Therefore, these results show for thefirst time that high frequency electromagnetic and electrostatic waves have thecapacity to regulate the global structure of collisionless shocks.

Quantified Energy Dissipation Rates: Electromagnetic Wave Observations in the Terrestrial Bow Shock