Magnetic and Pressure Probes on the HyperV Contoured Coaxial Plasma Accelerator*

Magnetic and pressure data from several contoured-gap coaxial railguns is presented. These plasma guns use an injected plasma annulus and shaped inner and outer electrodes to mitigate the blow-by instability. Passive magnetic probes and photodiodes search for evidence of the blow-by instability and azimuthal asymmetries. Stagnation pressure and velocity are compared for different size guns and for different driving voltages and currents.