I've noticed ultraviolet laser diodes have come out and I'd like to use a UV laser to create a path of ionised air along which a pulse of high voltage electric current can travel. I've heard of people doing it before so I know it's possible. I want to ask if anyone can suggest how many milliwatts of laser output would be required to ionise the air in this way. Also, how would the temperature and humidity of the air affect the ionisation? I realise increased humidity would aid the flow of electric current.