Characterization of the ACE 4 catcher´s mitt POS-load configuration

Summary form only given. A growing body of evidence suggests that the performance of a high density plasma opening switch (POS), driving a bremsstrahlung load, is controlled by low levels of plasma downstream from the POS. We discuss here the "Catcher\´s Mitt" configuration demonstrated on ACE 4 at current levels approaching 4 MA and for conduction times exceeding 1 /spl mu/s, as an approach to controlling downstream plasma in high I/sub c/*T/sub c/, POS. Under these conditions the ACE 4 POS demonstrated an open impedance greater than 0.5 /spl Omega/ and generated in excess of 1 MV when driving a pinched e-beam load. The Catcher\´s Mitt geometry was based on a phenomenological model which was developed to explain experimental observations on ACE 4. Optimization and the application of this approach to other pulsed power machines requires a more basic physics understanding of the interaction between the POS and the downstream Catcher\´s Mitt geometry. This paper reports on recent tests and analyses aimed at achieving that basic understanding.