POS-load coupling performance on Ace 4

Summary form only given. The ACE 4 POS is being developed as a monolithic switch option for DTRA´s DECADE quad. Although the ACE 4 POS performance in terms of conduction time, 1 /spl mu/s, conduction current, 3.5 MA, and POS voltage generation, 2.5 MV, has been sufficient, a demonstration of efficient coupling to a bremsstrahlung diode load has not been demonstrated. The POS-load coupling issue appears to be dominated by plasma flow between the POS and the load. Increasing the POS to load distance has partly solved this problem on other pulsed power machines such as DM1 and HAWK, but does not appear to be a practical solution on ACE 4. Results from load coupling studies on ACE 4 will be presented which address the issues and potential ways of eliminating plasma downstream of the POS.