A Guillemin type E pulse forming network as the driver for a pulsed, high density plasma source.

A Guillemin type E pulse forming network (PFN) has been designed, developed, and tested for its application in generating high density (~1 x 1018 m-3) plasmas. In the present study, plasma thus generated is utilized to investigate the interaction of high power microwaves (HPMs) with plasma in an experimental architecture known as SYMPLE (System for Microwave PLasma Experiment). Plasma discharges of ~100 μs (max) duration are to be produced, by delivering energy of 5 kJ stored in a PFN to the plasma source, a washer gun. The output of the PFN, in terms of its rise time, flat top and amplitude, needs to be tailored, depending on the experimental requirements. An ignitron (NL8900) trigger generator (ITG) is developed in-house to control the PFN discharge through the gun. This ITG is also to be used in a circuit that synchronizes the HPM and plasma shots, to ensure that HPM-plasma interaction takes place during a temporal regime where appropriate parametric conditions are satisfied. Hence it is necessary to retain the jitter within ±2.5 μs. Further, requirement on plasma quiescence (~10%) necessitates maintaining the ripple within 5%. The developmental work of the PFN, keeping in view the above criteria and the test results, is presented in this paper. The parameters of the PFN have been analytically approximated and verified with PSPICE simulation. The test results presented include rise time ~5-8 μs, flat top variable in the range 20-100 μs, ripple within ~1.5%, and jitter within ±2.5 μs, producing quiescent (<10%) plasma discharge meeting the experimental requirements. [ABSTRACT FROM AUTHOR]