High Voltage

I am interested in high voltage, and how dealing with electricity is different at higher voltages.  However, I wanted to be very careful and very safe in doing these projects, so I started with just trying to produce a spark gap from a flyback transformer.   So I designed a simple 555 timer circuit that would trigger the gate of an N channel power mosfet.  The mosfet was connected to the input of the flyback transformer.  I then used a third hand to hold the HV output (secondary winding) near the ground of the secondary winding.  When energized, this produced a purple/blue spark of about ¼ inch.   I approximated this to be about 6KV based on the breakdown voltage of air (1MegaVolt per meter).   I was discussing why the spark was smaller than I thought it should be, when it occurred to me that the transformer is an inductor, and maybe my clock frequency from the 555 timer was too high.  Inductors don’t pass high frequencies very well.  So I lowered my clock frequency by changing the resistors on my 555, and got a spark that was almost 1 ¼  inches long.  I estimated that to be around 30Kv.
I took this output and created a lightning storm in a light bulb.  I put the HV output to the bottom of the light bulb, and taped a piece of aluminum foil to the back of the bulb and attached the ground to the aluminum foil.  This creates a lightning storm in the bulb.  However, I need to heatsink the mosfet better.  I can’t run the storm for long, as the mosfet gets very hot. 
My next HV project is to design and build a HV plasma arc speaker.  This will be challenging, especially in switching the high currents required and controlling the heat generated so that I don’t damage the circuitry.