A Cesium MHD Arc Jet

Abstract

A cesium‐fueled magnetohydrodynamic arc jet was operated between 4 and 12 kW at magnetic field strengths up to 1000 G. Electrostatic probe, spectroscopic, and microwave measurements were made on the exhaust beam. Beam momentum was determined from the deflection of a downstream sieve. The magnitude and position of Hall currents were determined using magnetic‐loop pickup coils. The over‐all arc voltage is a linear function of applied axial magnetic‐field strength. The thrust is a linear function of the product of the arc current and applied axial magnetic‐field strength, and is of a magnitude too great to be produced by the measured Hall currents. A partial theory is developed that describes the functional dependence of the arc voltage and thrust. Data are presented that show mass entrainment was present and that when the arc is operated with mass entrainment the exhaust velocity is predicted by the Alfvén ``critical velocity.''