Electric and magnetic fields of shock fronts

The strong charge carrier gradients in ionizing shock waves produce electromotive forces (emf) which are responsible for space charge fields, electrical currents and magnetic fields. This paper attempts to measure the magnetic field, and studies the open circuit electric field and the current under load in standing shock fronts. Voltages were obtained using as working fluid either argon gas or the reaction products of acetylene oxygen detonations. The plasma of the shock front acts like the hot electrode in a thermionic convertor or a thermocouple. The supersonic flow provides the power to maintain the configuration and prevents heating of the cold electrode. Electrical power generation with the emf produced in standing shock waves can therefore be considered as an alternate principle for direct energy conversion from high temperature supersonic flow fields, in a temperature range where so far only MHD generators may be applied.