Adjustment of DPF Implosion Time and Geometry with Controlled Injection

A classic gas-filled DPFs are controlled by the geometry of the electrodes as well as the pressure of the gas fill. NRL DPF experiments on the Hawk pulsed power generator explored the alternative - local plasma and gas injection into the DPF device, which prevents breakdown and short-circuiting upstream at later times. At the same time, such injection gives a bigger control over implosion timing, independent of the device geometry. This will allow quick fine-tuning during the run of the experiment. In a series of MHD simulations using the Athena code, we study how different types of plasma and gas injection affect the implosion. For example, one may inject a plasma column perpendicular to the axis or at an angle, to counteract inhomogeneity of the j x B force. This may allow injecting less gas, but have longer delay times before the implosion. The location of the implosion and the mass delivered to the axis can also be controlled.