On Feb 7, 11:01 pm, Mike Williams <nos...@[EMAIL PROTECTED]
> wrote:
> I can't find the equations for the dispersion of laser beams, but I
> would have thought that at a distance of 300km the beam would so wide
> that it wouldn't make an effective weapon even against black targets.
A 1 micron IR laser focused through a 10 meter lens will have an ideal
spot diameter of around 40 cm at 300 km (in practice, the spot will be
a bit larger, but not too much larger for high quality beams). If the
laser has a 10 MW output, it will be delivering 800 kW per square
centimeter. This is intense enough to propagate a melt front into
iron at a rate of around 10 cm/s.
http://panoptesv.com/SciFi/DamageAverage.html
> A laser is useless as a point defence weapon against unsilvered kinetic
> slugs. You take just as much damage from a kinetic slug that's been
> melted by a laser as from a solid slug.
If you destroy the guidance of the projectile, it is trivial to
maneuver out of the way. Propellant tanks can be holed, chemical fuel/
propellant can be ignited, rocket motors can be damaged, and if the
projectile is under thrust even merely weakening the casing can cause
it to explode. All of these let you easily avoid the incoming round.
At close ranges, you will also be able to va****ize parts of a solid
slug, breaking it apart into pieces small enough for your armor to
handle or using the reaction of the jet of hot plasma blasting off the
surface to deflect the kinetic.
Luke
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