Re: Colonists and Weapons

Scott Clinton wrote:

> >Vaporising a 20 cm long wound channel with a sectional area of  one
> >square centimeter requires delivering 45 kilojoules to the target...
>
> >Ignoring all losses and assuming that all efficiencies are 100%,
> >the solar collector area is sixty square metres...
>
> >...it would be wildly optimistic for the efficiencies of
> >either the laser or the solar collector to get above 50%.
>
> All of these statements are based on CURRENT, 2001 technology, not SG2
> sci-fi tech and thus are basically mute.

Minor nit: current 2001 tech puts the theoretical (not technically
possible)
efficiency of a free-electron laser (can't get much more efficient than
these)
at 25%, and that number comes from a wildly optimistic SDI research
project.

>
>
> >Until someone starts burning holes in living things, we will not know
> >how uaseful the 45 kilojoules guess is.
>
> And how are these assumptions about LASERS any less acceptable than
those
> even less knowledge-based assumptions we all are making about gauss
weapons
> and hover tanks(for example)????  At least we know some of the the
> limitations of LASER and humankind will have more time to
perfect/improve
> the LASER.

Hover, as opposed to grav, tanks are an engineering problem, not a
physics
problem.  The flying bedstead is proof of concept (vehicle that flies
without
aerodynamic lift, just thrust).  The hundred tonne hovertank will
require huge
amounts of power, but the backpack-sized polymegawatt fusion reactor is
a sci-fi
staple (without it, none of our toys will work).  Gauss weaponry has
less of a
gap between what they are and what we wish them to be, than lasers. 
Aside from
embarrassingly large power requirements and bulky size, they could
almost be
used to kill tanks now.

>
>
> >Your wide beam mode will require huge amounts of power.
>
> Based on CURRENT, 2001 technology, not SG2 sci-fi tech...  Not to
mention
> (again) 100+ ton tanks can fly and humans can wear powered armor due
to
> advances in power generation but this same universe will not allow not
> enough power for a more efficient LASER to burn through a enemy on the
> battlefield???

A beam with an area of sixty square meters that has the same energy
density as a
beam area of one square centimeter will require six hundred thousand
times the
power.	The wide angle beam will be one of very weak, very narrow, or
very close
ranged.  Being able to make 100 tonne vehicles fly will never impart the
abilty
to divide ten by two hundred and get an answer of two.

>
>
> I just seems to me that some are prejudiced against LASERs as future
> battlefield weapons because they already exist, and thus we know some
of
> their CURRENT limitations.  This is an advantage, NOT a disadvantage. 
Until
> you know a technologies limitations, you can hardly work to improve
it.
> Whereas weapon systems that are not even on an engineer's drawing
board are
> accepted without qualms (that I have heard on this list) when we don't
even
> have a realistic clue as to what their limitations might even be
(gauss
> weapons being one)

There are experimental gauss weapons, they were developed as part of the
SDI
project.  One limitation is anchoring the rails that pass current to the
projectile, as they are strongly attracted to each other.  Another is
the high