CLAMP SYSTEM FOR THE PHAROS 2-MJ CAPACITOR BANK.
NAVAL RESEARCH LAB WASHINGTON D C
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A clamp system is now in operation on the Pharos magnetic-compression experiments two-megajoule primary capacitor bank. Clamping the discharge circuit at the current maximum about 17 megamperes with 16 microseconds risetime converts the normal damped oscillatory waveform to an aperiodic current with an exponential decay time constant of more than 200 microseconds. This conversion permits study of the plasma in a region where the confinement time is no longer limited by the duration of the confining field. An important feature of the clamp-circuit design is the isolation of individual clamp switches by the starting switches during the capacitor charging period. Thus, only a small fraction of the total bank energy is dissipated in the clamp switch in the event of a prefire. The 420 parallel clamp switches, developed at the Naval Research Laboratory, are a variation of the Pharos air trigatron starting switch, except that they are housed in a commercial Pyrex tee and evacuated to one millitorr. The clamp-switch terminals, which are an integral part of the electrodes, allow direct mounting between the capacitor high-voltage stud and ground plates. No modification to the existing capacitor bank was required for installation, so the experimental program was not disrupted. Author
- Electrical and Electronic Equipment
- Plasma Physics and Magnetohydrodynamics