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Re: HV + laser beams
Subject: Re: HV + laser beams
Date: Wed, 21 May 1997 21:09:52 -0800
From: Greg Leyh <lod-at-pacbell-dot-net>
To: Tesla List <tesla-at-pupman-dot-com>
References: 1
Alfred A. Skrocki wrote:
> > Several hundred feet? I am skeptical, as the laser needs to have an
> > intensity sufficient to ionize the air along the entire light path.
> > A 100kW pulsed laser can ionize the air if focussed to a point, but
> > tens of megawatts are required in order to ionize an appreciable
> > linear path to the point of conduction. Even though a 10MW pulsed
> > laser is relatively available (large table top, <1M$), I doubt that
> > even 10MW pulsed could ionize more than a 10 foot path thru the air.
>
> Hi Greg, what you have to realize about Nitrogen lasers is they
> operate in pulsed mode and even though their average power may be
> only a few watts the pulsed beam can approach the megawatt range.
> It's as if you charged a capacitor with 1 watt hour of power and
> discharged it in one millionth of a second, that would effectively
> be 36 billon watts but only for one millionth of a second. In the
> case on the UV laser even though the path is ionized in fractions of
> a second it takes much longer for the path to stop conducting so for
> all intents and purpose it may as well be a continous conducting path.
Please note that I was, in fact, talking about pulsed lasers in the
previous missive.
At work we have a YAG-pumped, Ti-Sapphire laser, that produces 15W
average
and 240kW peak pulsed. It's a fun laser to play with -- if the beam is
focussed using a short focal length lens, a pinpoint electric arc forms
at the focal point, suspended in free space!
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