  We present the first quantified measure of the rate of energy dissipated per
unit volume by high frequency electromagnetic waves in the transition region of
the Earth's collisionless bow shock using data from the THEMIS spacecraft.
Every THEMIS shock crossing examined with available wave burst data showed both
low frequency (< 10 Hz) magnetosonic-whistler waves and high frequency (> 10
Hz) electromagnetic and electrostatic waves throughout the entire transition
region and into the magnetosheath. The waves in both frequency ranges had large
amplitudes, but the higher frequency waves, which are the focus of this study,
showed larger contributions to both the Poynting flux and the energy
dissipation rates. The higher frequency waves were identified as combinations
of ion-acoustic waves, electron cyclotron drift instability driven waves,
electrostatic solitary waves, and whistler mode waves. These waves were found
to 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) energy
fluxes 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 rates
were found to be in excess of four orders of magnitude greater than was
necessary to explain the increase in entropy across the shocks. Thus, the waves
need only be, at times, < 0.01% efficient to balance the nonlinear wave
steepening that produces the shocks. Therefore, these results show for the
first time that high frequency electromagnetic and electrostatic waves have the
capacity to regulate the global structure of collisionless shocks.
