Design and Optimization of a Flow Switch for Optimized X-Ray Yield on Z

Summary form only given. In wire array Z-pinch applications it may be desirable to have a faster rising current pulse to decrease the wire array ablation period and wire array implosion time. A decrease in array implosion time will increase the implosion velocity and possibly increase the peak radiated X-ray power at stagnation. Faster rising current pulses may also permit high X-ray power from smaller diameter wire arrays that could enhance the X-ray drive temperature from more compact hohlraums. In this work, we present initial results from a design study for a plasma flow switch for the Z accelerator. We would like to compress the pulse by a factor of two with a flow switch that allows the current to be stored in the vacuum for up to 50 ns before it is delivered to a wire array load on the Z Accelerator. This would double the dI/dt of the Z accelerator from the current 2.4times1014A/s, to about 5times1014A/s, possibly allowing wire array implosions as short as 50 ns for a 20 mm diameter wire array, or perhaps permitting final implosion velocities of greater than 20 cm/mus from 10 mm diameter wire arrays. We use 2D r-z simulations of a flow switch with the ALEGRA MHD code. Different geometries, materials, flow switch mass, and wire array mass and other conditions were tested and compared in order to obtain an initial flow switch design