Load current pulse shaping on a nanosecond PFL-based accelerator using dynamic LCM technique
Résumé
Oral presentation Load Current Multiplier (LCM) continues to be successfully applied on Zebra at UNR. Here we consider further, expanded applications of LCM. Time-shaping of magnetic pressures on pulsed facilities is useful for such a number of High Energy Density Physics (HEDP) applications such as dynamic material properties studies1,2, high gain ICF research3 and instability growth studies4. The Dynamic LCM (DLCM) technique was recently developed for profiling the dynamic pressure ramp with good reproducibility on the microsecond SPHYNX generator (left plot)2. The present report analyses applications of this technique on Pulse Forming Line (PFL) nanosecond generators. The right plot presents simulated load currents Id and load liner accelerations ad for a 0.2 Ω PFL with the voltage Veq. without (dashed lines) and with (solid lines) DLCM for the imploding solid-state load of Ref. 2. DLCM here is an additional compact (5×10 cm) hardware installed between the PFL and the load with an imploding annular plasma shell inside. We report circuit analysis and MHD simulations that identify critical DLCM and load configuration parameters allowing to control the load current ramp. We demonstrate that not only the load magnetic pressure time-dependence can be controlled in the HEDP loads above but also the load current amplitude can be increased with respect to the direct PFL-driven case (right plot).