Design of Corona Rings

I am developing a 100kV pulse system which is made in series with the 3kV modules. In each module there is a IGBTs, diodes and other components. When this system deliver the 100kV output, it will create corona which will create the problem and could discharge the system. Now, how to design corona rings for the modules? What should be size of the ring?

May I suddest that the most important things things to keep in mind, are no points, and no sharp edges. Another suggestion is to look at fitting a hollow (for weight reduction) metal sphere at the end of your wire. This was done by Oliver Lodge in his wireless experiments, and by radio station HCJB in the Andes mountains to prevent their dipoles from melting at the ends due to coronas in the thin atmosphere. Incidentally a little trivia here, in that HCJB invented the quad loop antenna which totally eliminated coronas.

Dear sir
Since this is a module base power supply. Actually it is a marx generator which include igbt in place of resistor for controlled charging and discharging of capacitors. So it is not possible to put some metal sphere at every IGBT point as all IGBT and diode float at 100kV, 97kV, 94kV, 91kV......So sharp point of these IGBT may start discharging. So do i need to put the corona ring or sphere at each IGBT point or can I put at different location like...at 100kV, 80kV, 60kV, 40kV, 20kV floatinng IGBTs.

Oh I see. The corona ring sits at or near the FETs so as to be at the same potantial (I think). Also WOW, a Marx generator!. I could use one of those to generate an EMP to test my Mulpin Prototype (EMP proof electronic components / PCBs. I used a microwave oven amd the PCBs worked after 20 or so 212 second exposures. See proof of concept video (spectacular it is! on www.mulpin.com. I would very much appreciate any information on how you build your Marx Generator so I can make one as well. Cheers and very good luck (if you need luck). Alternatively I can send you some PCBs to test for me if you would do.

Dear sir
my marx generator is actually a pulse power supply. i.e. it is controlled so i need to use IGBTs and then their trigger circuits & also isolation problem. All these things make it complex and costly. But for your purpose you can make a uncontrolled marx generator. it will be easy and also will serve your purpose as i have seen your proof of concept video. You could simply use resistors for charging the capacitors and use spark gaps for discharging the capacitors.