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Re: Coil ideas for experiments

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Tesla List wrote:

> Original Poster: ANTarchimedes-at-aol-dot-com
>
> In a message dated 4/14/2000 12:58:24 PM US Mountain Standard Time,
> tesla-at-pupman-dot-com writes:
>
> <<
>  Actually, you'll need 10^12 W/cm^2.  I talked to one of the optics profs
> today.
>  We worked out a nice plan:
>
>  Pulsed (CO2, I think) laser at 10mJ per pulse, 10ns Pulses, at 10 pulses per
>  second.  Focus the beam down to a spot size of 10um, and you have your
>  10^12W/cm^2.
>
>  The down side is that this is still a pretty huge laser requring some
>  interesting optics to handle the high power.  Also remember that m ost
lasers
>  are less than 10% efficient:  put in 1kW, and you'll get at most 100W laser
>  (continuous).  I'm not certian how much power input would be needed for this
>  device, however.
>
>  The prof did say that one could use a prism, or accousto-optic modulation to
>  make figures that the arc could/would follow.  I must admit, it would be
> pretty
>  sweet to see a TC spit out streamers that trace out a square, circle, or my
>  name  :-)
>
>  I still feel that using a laser this large in a non-laboratory environment
>  could
>  have some serious safety problems.
>   >>
>
> So with 10% efficiency, 10 mJ per pulse, and 10 pulses per second (What's
> with you and the number 10?), it should use about 36 watts (joules) and hour
> with the assumption that 10mJ is equal to 1/100th of a watt.  So then, if
> powered by an ordinary 120vac source, it should pull about 1/4 an amp.
> That's not too much power.  The problem would be in acquiring the equipment.
> Outside of a lab, it shouldn't be too dangerous as long as it isn't pointed
> at any living things, man made or flammable objects, or reflective surfaces.
> In short, point it at a dark rock.  The only problem I see with this idea
> would be in preventing the laser from traveling towards the laser and arcing
> toward it's power source.  In this case, a system of prisms would be
> desirable.  Perhaps I should speak with my optrician about his laser to see
> if a system of that type would work.

First of all, a Joule is *NOT* a Watt.  A Watt is a unit of power, and a
Joule is
a unit of energy.  They are related: W = J*s  (s == second).  Also, 10mJ is
.01J
(not to be mistaken for mircoJoule).  I like the number 10 because it's easy to
calculate with ([10^6]^2, not [2.5*10^6]^2).

J = w/s => .01 = W/10^-8 =>  W = 10^6Watts per pulse.  Times 10 pulses per
second
= 10MW.  The laser then puts out 100MW.  That's a darn big laser!  Of
course the
avearge current draw isn't quite that high ;-)  I couldn't tell you what it
is, as
I've had no experience with pulsed lasers.

A high-power pulsed laser is very dangerous.  I've seen lasers this
powerful blast
heavy objects into the air (military and NASA was experimenting with pulsed
lasers
as new launching mechanisms).  I doubt that a laser this large could be
obtained
by a "lay person" for less than one hundred thousand dollars (US), although I
never really asked about price (the 10mJ/10ns pulse told me that this idea
isn't
really for an ameture to be playing with).

This thread is getting quite off topic....  (Sorry, Terry)*

Mark

<<<* - Please keep the laser triggered gap topic practical and about firing
spark gaps - Terry>>>