Plasma Window for containment of high pressure gas for use with a gas Charge Stripper

The so-called Plasma Window is a DC cascaded arc whose function is to greatly restrict gas flow from a high pressure (upwards of 300 torr) chamber to a low pressure side (order of 0.1 torr). This is motivated by its potential to contain a gas charge stripper on a beamline of a high intensity heavy ion accelerator without the need for solid windows that would obstruct beam passage1. At the National Superconducting Cyclotron Laboratory (NSCL), a test stand for this Plasma Window has been developed to study how this flowrate restriction is impacted by plasma physical properties. Proposed mechanisms for this flowrate restriction are firstly a significant increase in temperature causing greatly enhanced viscosity in the plasma channel, and secondly a choked flow condition being established through gas speed reaching supersonic conditions2, Our gases of interest in this study are pure Ar and He.