Re: Orion Drive space battle

Luke Campbell wrote:
Paul F. Dietz wrote:

One interesting thing you can do with lasers is cool with them. That is,
if you have an external source of laser light, it can refrigerate an object
by anti-Stokes scattering off resonant scatterers. This has been demonstrated
in the lab with rare earth ions in some exotic glasses. Perhaps this is
a solution to the spacecraft cooling problem?

For a while, I tried to come up with a way to use laser cooling and
trapping to cool and focus neutral particle beams for use as long range
space beam weapons. I never came up with much that was practical, but
maybe it can be done.

The use of a laser to cool a spacecraft is interesting. Instead of
waiting for spontaneous radiation to cool you off, you can exchange
your heat with a high intensity beam. My guess would be that you would
focus the laser into antiparallel propagating beams (perhaps along the
three cartesian axes) across a cell of gas with an absorption resonance
just above the laser frequency, and use the "optical molasses"
technique to cool the gas. This gas, would, of course, also be the
working fluid for a heat exchanger with the hot parts of the
spacecraft.

Note that this would not solve the stealth in space issue that is often
associated with the heating issue - you would be glowing very brightly
from the scattered laser light. You can't intercept the laser light to
prevent it from being detected, because then you'd be getting all that
heat back, plus much much more heat from the absorption of the beam
itself. The best you could do would be to reflect the beam in a known
safe direction. Since your scattered light is no longer coherant or
directional, you are stuck with using imaging optics for focusing it
into a beam, with all the attendant problems thereof.

I'm reminded of the 'refrigerator laser' from _Sundiver_.
By this method, you don't end up with a coherent beam of light to shoot
off, but you do end up with a restricted window of frequencies. I
wonder if it might be at all useful in something like a _Sundiver_
situation, where the ship is immersed in some medium, to act as a heat
pump or to tune your radiating frequencies so that as much of the
radiation as possible avoids getting absorbed right close to the ship.

-l.

.

Relevant Pages

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