A little background: I'm a mechanical engineering graduate student with a focus in materials, so electrical engineering is not my core background. I'm conducting research on plasma surface treatment of metals and there's a lot of variables I'm trying to control reliably, but when it comes to the electrical aspect of the project I'm struggling a bit. Here's a rough schematic of the electrical aspect of my text fixture:
Starting with the left box, from left to right:
DB1: wall power, 110V, 60 Hz, 20 amp breaker
Bridge rectifier, full wave, single phase: 50A max forward current, 1000V reverse voltage
C1: 500uF capacitor
L2: Self wound inductor/choke 50 turns high voltage side, 50 turns low voltage side, 55mm OD x 35mm ID x 14mm H, wound with 12 gauge magnet wire (I haven't measured the inductance, sorry!)
D1: 6amp 20kV diode
V2: spark gap, basically two 12 gauge copper wire "rails", sandwiched between insulating sheets (PTFE), and two grade 52 neodymium magnets. High voltage ignites a plasma between the rails, and the lorentz force accelerates the plasma, out of the gap and onto test samples.
R1: Power resistor bank to avoid tripping the breaker
Right now the box on the right is a cheapo AA battery powered High voltage boost converter (~20kV).
The circuit on the left provides a (relatively) high current-low voltage DC power supply, and the circuit on the right strikes the spark gap with high voltage and ignites the plasma.
The issue I'm running into is that I really need to push the current level of the plasma jet to continue pursuing my research. The diode was $40, and I've burnt out 3 so far due to overcurrent(1 single, and then 2 in parallel). I'd like to get the current to around 50 amps, but the high voltage diodes are extremely cost prohibitive.
So here is my question: Is there an equivalent or similar circuit, free of high current high voltage diodes, which can ignite a plasma with a high voltage/low current source, then immediately dump current into that plasma from a low voltage/high current source. The boost converter results in a pulsed system, it would be a bonus to have a semi-steady state system.