Experimental characterization of a puff-gas z-pinch plasma prior to implosion

An argon annular puff-gas z-pinch has been experimentally investigated during the early phase of the current pulse using a magnetic flux probe and streak interferometry. The current is seen to follow the flared outer edge of the gas jet and to be returned primarily at axial positions z<15 mm by six posts supporting the wire mesh anode. A theoretical estimate of the skin depth agrees with the measured ∼1-cm thickness of the current sheath. The electron to neutral density ratio is determined to be peaked both near the posts and near the cathode.