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Re: Laser guided Tesla Coil



Original poster: Jim Lux <jimlux@xxxxxxxxxxxxx>

At 08:32 PM 2/15/2007, Tesla list wrote:
Original poster: FIFTYGUY@xxxxxxx
In a message dated 2/15/07 9:28:11 P.M. Eastern Standard Time, tesla@xxxxxxxxxx writes:

>Yep, joules in nanosecond pulses or giga-watts can cause the air to
>"snap" ionize in front of some pulsed Nd-Yag lasers

My issue with the whole concept of using lasers to pre-ionize a path for an electrical discharge is:

    You can't ionize the entire channel at once.
Once the air is ionized, it is no longer optically transparent. If you ionize a spot of air near you, you can't ionize the spot of air in front of it because you can't "see" it. If you start by ionizing a spot of air closest to the target, then you'd have to ionize the spot just a little closer to you, then a spot a little closer, working your way back. For any "useful" distance, that's a lot of closely-spaced spots that have to be ionized. I have no idea, let's say the target is 100 meters away, and each "spot" becomes an ionized patch the volume of 1cc. That's 10,000 spots to ionize. The time scale would probably be what, 1/100th of a second before sufficient ion decay to make the spot useless (based on Tesla coil minimum effective BPS). So those 10,000 ionized spots would have to happen at 1 Mhz.


One scheme used by the people using lasers to guide lightning actually uses multple lasers aimed at a spot to cause breakdown (or at least heating). then they move to another spot, etc. and form a chain of all these little hot spots. So the spark isn't being guided ALONG the beam, but a laser is being used to do the leading.

Same sort of idea might work with large curved mirrors with a short focal length to establish the high field at the focal point.