Pseudospark-Based Power Modulator Technology for Transient Plasma Ignition

Studies of power modulator technology for transient plasma generation for pulse detonation engine ignition are reported. Transient plasma ignition can significantly reduce delay times in static and flowing systems. The igniter operates reliably in repetitive modes with pulse length down to 50 ns, and in some situations, with less electromagnetic interference than conventional spark ignition. Pseudospark-based line type pulse generation is described in this report. Research directed toward more compact versions of the pulse generation technology, including investigations of miniaturized back-lighted thyratron switches, is briefly discussed. During the previous year, experiments have been conducted in collaboration with researchers at the Naval Postgraduate School, and Wright Patterson Air Force Research Laboratory, testing ignition of pulse detonation engines (PDE). These experiments demonstrated considerable (factors of 2 to 5) reduction in delay to detonation, and improvement in repetition rate, while retaining low energy cost. The results suggest a potential solution to one of the most serious limitations to the development of PDEs. Desired pulse amplitude depends on the exact geometry of the combustor, ignition chamber, as well as corona electrode. Typical voltages employed are 50 kV - 70 kV for these studies, with pulse energies of the order 100 mJ to 1 J. The pulse generator employed a pseudospark switch. The principles of the pulse generator reported here are described in the paper submitted for this meeting last year. It is designed to deliver pulses of V_p=90 kV peak amplitude and tau_p=50 ns duration