Abstract
In order to clarify the electromagnetic acceleration mechanisms of an applied-field magneto-plasma-dynamic arcjet (MPDA), magnetic fields are measured in detail near the MPDA outlet. Plasma current density is calculated using the Maxwell equation (rotB=μ0j), and then spatial distributions of Lorentz forces (j×B forces) are evaluated. A uniform external magnetic field is deformed by a strong diamagnetic effect near the MPDA outlet, and as a consequence, a converging magnetic nozzle configuration is formed. It is found that an axial Lorentz force Fz (=jrBθ-jθBr) is almost eliminated by the deceleration force (the jθBr force), which results from the diamagnetic effect. The deceleration force can be converted to the acceleration one in an externally-applied diverging magnetic field.
