At 03:34 PM 12/7/00 -0800, Eric Cordian wrote:

     It appears that the tactical chemical laser the US has been hoping
     to
     deploy to protect the Zionist Entity from rockets launched by
     Hezbollah
     guerrillas in southern Lebanon is, in the words of its developers,
     "not
     ready for action."
     [1]http://www.newsday.com/ap/text/international/ap796.htm
     According to the defense department blurb on the system, called THEL
     ([2]http://www.smdc.army.mil/FactSheets/THEL.html), the system
     employs
     deuterium fluoride as the lasing medium.
     Since deuterium is somewhat more expensive to produce than ordinary
     hydrogen, one wonders why the system has been designed to work with
     deuterium.  Is it because the government does not want fuel for it
     to be
     easily produced, should the design fall into enemy hands.
     Or is there some engineering advantage to using deuterium?  Does
     excited
     deuterium fluoride have some wonderful spectral line in exactly the
     right
     place, that pedestrian hydrogen fluoride does not?
     Any chemical or nuclear engineers here who could answer the question
     of why deuterium is more desirable?

   That's exactly it. Deuterium-Flourine (and I think Deuterium-Iodine)
   have a prominent emission line which matches up nicely with CO2.  In
   practice, the DeF/DeI are hypergolically combined in the combustion
   chamber (that is they combust immediately upon contact) producing an
   impressive power output.  Somewhere inside or just outside the nozzle
   CO2 is injected and turbulently mixed.  Two parallel mirrors
   perpendicular to the exhaust lase the pumped up C02 and other
   (tracking) mirrors direct it to the target.  Unlike most other high
   power lasers these babies are CW, not pulsed, and capable of generating
   multi-megawatt beams. (They work exceptionally well in space if you can
   keep the fuel/oxidizer from leaking and make sure the exhaust doesn't
   dissolve the weapon)
   This was a major Naval project when I worked at TRW in the 80s called
   Mid-Infrared Advanced Chemical Laser (MIRACL)
   See
   [3]http://www.space.com/missionlaunches/launches/laser_shootdown_000926
   .html
   or search under "TRW chemical laser"
   steve

References

   1. http://www.newsday.com/ap/text/international/ap796.htm
   2. http://www.smdc.army.mil/FactSheets/THEL.html
   3. http://www.space.com/missionlaunches/launches/laser_shootdown_000926.html