R. D. Ford

Inductive storage pulse-train generator

Utilization of inductive storage in production of intense charged particle beams, laser beams, and hot dense plasmas of interest in thermonuclear fusion studies and in other research areas is very attractive because of its inherent compactness associated with energy storage in the form of magnetic fields. A major problem in utilizing inductive energy sources with sufficient output power for such beams and plasmas is the development of an opening switch. In some instances, repetitive pulse output is required, so that switches must open repeatedly at a frequency determined by the needs of the experiment. If only a small number of pulses is needed, then use of one switch per pulse in the train becomes a practical method for generating pulse trains with peak power determined by the performance of individual switches. Formation of pulse trains with peak pulse power in the range of 109to 1010W was studied. This study included the investigation of single-switch elements to determine methods for extending the operating power to higher levels.

High recovery voltage switch for interruption of large currents

An opening switch for interrupting 50‐KA currents in inertial–inductive storage systems has been developed. A switch arc voltage of 2 kV (3.3 kV/cm) has been obtained using explosive cutting of the current‐carrying sheet. A single‐gap switch interrupts a current of 7 kA per cm of sheet width in ∼10 μs. Recovery fields of up to 100 kV/cm were achieved at 2 kA/cm, at 35 μs after interruption. The switch is designed for long (∼1 s) current‐carrying time associated with homopolar generator charging of inductors.

Effect of mechanical agitation on fuse opening switch efficiency

It is demonstrated that an exploding wire fuse opening switch comprising aluminum wire in water can be made more efficient by mechanically agitating the wire while it is being exploded. The electrical current flowing through the wire collapses faster, generating a higher voltage output when the arrival time of the agitating source at the wire material is well selected. The agitation appears to facilitate the dispersion of the molten metal within the water tamper so that the electrical energy input necessary to open the switch is reduced.