MHD power extraction from cold hypersomc air flow with external ionizers

The paper analyzes a novel concept of hypersonic cold-air MI-ID power generators with ionization by electron beams,f urther developingi deasa nd methodsp resentedin an earlier paper AIAA-99-3635 by the authors. Electron beams are shown to allow control and stable operation of MHD channels in cold highspeed flows. To avoid excessive energy cost of ionization and damage to beam-injection foils, electron beam current densities should be restricted to a few mA/cm² This means that the conductivity in electron beam sustained MHD channels would be substantially lower than in typical conventional MHD generators. This restricts the performance and calls for very strong magnetic fields,’ resulting in very high Hall parameters. The high Hall parameters cause ion slip and near-anode phenomena to become first-order issues. Example ID calculations of hypersonic power generator performance appear to. be promising. The paper also discussesp ossiblep roblemst hat could be causedb y hypersonicb oundary layers and electrode sheaths,i ncluding anodes heathi nstability and ways to avoid it.