The circuit is incredibly simple (below). It was re-designed from the old dual transistor flyback driver by Burak.This circuit only requires 4 parts, a 240 ohm power resistor, a 27 ohm power resistor, a 2N3055 power transistor and, of course, a flyback transformer. You will also need some enamelled 13-10 gauge wire for winding the primary and feedback coils and some insulated hook up wire. Don't forget the power supply, which should be around 12-20v at 3-5A, or just a car battery. In fact I used a car battery charger (13.5v) at 10A with a 3500uF filter capacitor (this cap is a must when dealing with oscillatory systems). Even with a 13.5 volt supply I was still able to draw an inch and a half of decent high frequency plasma, even using a lame half wave rectified cylindrical flyback.
My new confuguration is to the left. As you can see all of the parts are mounted on some smoked lexan. I added a terminal junction for easy connection and I used the so called "zap straps" for mounting the flyback. Note the lagre heatsink for the transistor which in infact not a 2N3055 but a power bipolar removed from an audio amplifier.
The power supply that I used for taking these pictures was extremely overpowered for this application (18v 100A), although the circuit only drew 3.44A, which is actually quite ineffecient (61.92W) if you think about it. You can see the reading in this image.
Flyback arc - 1.23mb