The resolved layer of a collisionless, high β, supercritical, quasi‐perpendicular shock wave, 2. Dissipative fluid electrodynamics

At a high β (2.4), supercritical (Mf ∼ 3.8), perpendicular (ΘBn1 ∼ 76°) shock, we have experimentally established for the first time a number of properties. The energy transformation within the resolved shock layer takes place in three stages: (1) the pedestal where ion gyromechanical energy is increased at the expense of the energy of the flow, (2) the ramp where flow energy is further diverted almost exclusively into magnetic and electron pressure, and (3) the downstream convected ion inertial length within which the ions start to make progress toward “thermalization” of the gyromechanical energy created in the pedestal. The scale of the magnetic ramp is clearly separated from that of the ion skin depth based on either of the Hugoniot asymptotic states. The cross-shock electrical profile has been determined in both the normal incidence frame (NIF) and in the deHoffman-Teller frame (HTF) by two different methods; the NIF potential drop was approximately 8 times that in the HTF. Potential overshoots were determined in both frames. The solar wind ion's convected inertial length in the downstream field is 10 times the scale of the magnetic ramp. The solar wind ions are shown to be significantly decelerated by the NIF electric force. Nearly all solar wind electrons have gyroradii less than the scale length of the magnetic field in the ramp; when E ≥ 500 eV this condition is no longer true. The thermal electron plasma remains well magnetized throughout the magnetic profile of the shock. The profile of the electron parallel temperature is closely correlated with that of the nonmonotonic deHoffman-Teller potential profile, suggesting that the parallel energy change of the electrons is largely reversible. The perpendicular electron temperature is often, but not always, proportional to the magnetic intensity. The average cross-field resistivity at the magnetic ramp was determined to be η⊥ ∼ 10−7 cgs by three independent methods; the spatial variation of the resistivity through the shock layer is significant, including order of magnitude variations throughout the downstream overshoot structures. The maximum resistivity occurs near the end of the first low-frequency magnetic overshoot. The parallel “resistivity” is usually negative and concentrated in regimes where the electron's HT potential energy has a local minimum. The cross-field diffusion of the magnetic field within the ramp balances the steepening of the field profile, as demonstrated by the equality of the magnetic Reynold's length and the exponential scale length of the magnetic ramp.