NONLINEAR TERMS IN THE GENERALIZING OHM'S LAW: A SCALE ANALYSIS.
Physical sciences research papers,
AIR FORCE CAMBRIDGE RESEARCH LABS L G HANSCOM FIELD MASS
Pagination or Media Count:
It is shown that a spatial gradient in the steady flow of an ionized gas introduces terms into the generalized Ohms law that represent an exchange of momentum between the electrons and the gas flow. Depending upon the flow geometry and gas compressibility this electrokinetic exchange can behave like a generator, a Hall current, or a resistive current. The scale of the phenomenon is L V, where V is fluid velocity, is electron-positive charge collision time. Electrokinetic conditions apply largely at boundaries. In a resistive medium with a static B-field, the principal condition for electron-flow interchange is that magnetic pressure dominate dynamic pressure. At the boundary of a plasma jet the scale over which EK terms are important is of the order of 1 mm. Only geometry and scale considerations are used in the momentum equation. The electrokinetic generation of surface currents is as fundamental for describing moving media as spacecharge effects are in the static case. Author