Design of a Fusion Propulsion System-Part 2: Numerical Simulation of Magnetic-Nozzle Flows

Abstract

Numerical simulations of magnetic-nozzle e ows have been successfully conducted in the interest of providing valuable insights and detailed design guidance to near-future experimental efforts. Quasi-steady modeling using heliumpropellantwithclassicalresistivitydemonstratesanearlyisentropicexpansionofthecone nedgastoexhaust speeds that exceed 270 km/s. For a stagnation temperature of 100 eV, approximately 70% of the thermal power is converted to thrust power (0.4 GW), producing 4.6 kN of thrust. Further expansion can lead to additional gains in thrust by utilizing the thermal powerthat is retained in the 20-eV plasma at the exit. In theinlet of the nozzle, near the plasma e eld interface, the development of nonuniformities in the magnetic e eld is exposed. For T0 =100 eV as much as 50% of the mass e ux is found to penetrate the current layer across the magnetic e eld lines. At e xed plasma pressure and applied e eld the layer at the throat increases in thickness from approximately 3 to 5 cm when the stagnation temperature is decreased from 250 to 100 eV.