Original poster: Jim Lux <jimlux@xxxxxxxxxxxxx> At 06:38 PM 2/17/2006, Tesla list wrote:
Original poster: Ian Macky <ian@xxxxxxxxx> How much laser power is needed to ionize air? Am thinking triggering and directing strikes. If you could ionize, the strike should follow that straight path, yes? The people at wickedlasers.com have green handhelds up to 300mw, compared to 5mw for typical red pointer. --ian
You need a heck of a lot more power to ionize air. To a first order, you need 3MV/m E field, which, given P = E^2/Z, so we calculate 3E6*3e6/377 = W/m^2, about 2E10 W/m^2. Say your beam is 1 cm^2, (1E-4 m^2).. a mere 2MW/cm^2.
You can get there with pulsed lasers (getting a megawatt peak power out of a N2 laser, for instance, isn't too hard). A moderate powered CO2 laser can ionize air if focussed down (usually using a suitable mirror) to a small spot.