Measurement of the expansion velocity of the plasma high-current vacuum arc discharge

In this work, we present experimental results on measuring the velocity of vacuum arc discharge plasma expansion. In the experiments, two designs of plasma guns were used. In the first version, the end of the arc discharge cathode was located below the plane of the anode, and the surface of the insulator separating them was parallel to the axis of symmetry of the plasma gun. In this design, the arc discharge plasma escapes the anode through a hole, the diameter of which coincides with the diameter of the cathode. In the second variant, the plane of the end face of the arc discharge cathode coincided with the plane of the anode, and the surface of the insulator separating them was located perpendicular to the axis of symmetry of the plasma gun. To obtain an image of plasma in the optical range, an FER-7 optical streak camera was used. Based on the results obtained, it can be concluded that the expansion velocity of the plasma of a high-current vacuum arc discharge does not depend on the design of the guns considered in this experiment.

EXPERIMENTAL TESTING BENCH FOR THE DIAGNOSTICS OF PLASMA GENERATED BY PULSED GUNS WITH THE DIELECTRIC SURFACE BREAKDOWN

The experimental testing bench “ETB-PG” was designed to study the operation of plasma guns. The constructional design of plasma guns with replaceable dielectric operating on the surface sparkover basis has been proposed. Discharge currents and voltages under atmospheric and vacuum conditions have been determined. The two types of discharges were detected in the pressure range varying from the atmospheric value to 10-5 Torr. An experimental Paschen curve has been plotted. A statistical dependence of the types of discharges on the number of pulses, the pressure in the chamber, and the breakdown voltage has been established. The results of optical studies of the plasma flow generated by plasma guns in the vacuum of 2∙10-4 to 2∙10-5 Torr have been presented. The propagation velocity of the plasma flow in axial and radial directions has been measured. The glow time of the injected plasma was determined for different types of the discharges. The spectrograms of the composition and degree of the plasma ionization have been obtained.

Taylor State Merging at SSX: Experiment and Simulation

We describe experiments and simulations of dynamical merging with two Taylor state plasmas in a Swarthmore Spheromak Experiment (SSX) device. Taylor states are formed by magnetized plasma guns at opposite ends of the device. We performed experiments with Taylor states of both senses of magnetic helicity (right-handed twist or left-handed twist). We present results of both counter-helicity merging (one side left-handed, the other right-handed) and co-helicity merging (both sides left-handed). Experiments show significant ion heating, consistent with magnetic reconnection. We suggest that the merged, warm state could be a suitable target for future magneto-inertial fusion experiments. Magnetohydrodynamic simulations of these experiments reveal the structure of the final relaxed, merged state.

Preparation of solid–solution type Fe–Co nanoalloys by synchronous deposition of Fe and Co using dual arc plasma guns

We succeeded in the efficient preparation of well-dispersed Fe–Co nanoalloys (NAs) using the arc plasma deposition method.