Magnetohydrodynamic Control of Hypersonic Flows and Scramjet Inlets Using Electron Beam Ionization

The possibility of controlling scramjet inlets in off-design conditions by operating a near-surface magnetohydrodynamic (MHD) system upstream of the inlet is examined. The required electrical conductivity in air is supposed to be created by electron beams injected into the air from the vehicle along magnetic field lines. A simple model of a beam-generated ionization profile is developed and coupled with plasma kinetics, MHD equations, and two-dimensional inviscid flow equations. Calculations show that an MHD system with reasonable parameters could bring shocks back to the cowl lip when flying at Mach numbers higher than those for which the inlet was optimized. The MHD effect is not reduced to heating only because the work by j X B forces is a substantial part of the overall effect. Power requirements for ionizing electron beams could be lower than the electrical power extracted with MHD, so that a net power would be generated onboard. Problems associated with high Hall fields are discussed