From: neufeld@helios.physics.utoronto.ca (Christopher Neufeld)
Subject: Re: Weapons systems?
Keywords: space combat weapons
Organization: University of Toronto Physics/Astronomy/CITA
Date: Wed, 11 Nov 1992 21:42:02 GMT

In article <1992Nov10.175623.577@newstand.syr.edu> pksuk@mothra.syr.EDU (Peter K. Suk) writes:
>----- max@west.darkside.com (Erik Max Francis) writes:
>
>>I've been thinking about combat in space, and am wondering if anyone has 
>>come up with any novel weapons/delivery systems.
>> [ ... ]
>>Anything else pop into mind?
>
>Mines - The author of _How to Make War_ opined that Japan
>	could have been subjugated by the mine-warfare campaign
>	in place at the end of WWII.  Traditionally _very_ cost effective.
>	Not popular with the brass, however.  (seems cowardly)
>
   I wonder how easy it is to mine space. Choke points are a bit harder
to come by when you have three dimensions of motion available and few or
no physical objects. You might want to interdict the approach to a
fortress or ship. It might make a good delaying tactic against boarders
trying to take a crippled ship. Just tossing mines out in interplanetary
space in the hopes that one of the bad guys will run into it seems like a
vast waste of funds.

>Also, there is a lot of room for variation in particle beams.
>In addtition to the commonly used particles and anti-particles, 
>there are the more exotic short-lived ones.  One of these (a muon,
>meson??  A physics friend told me about this, but I forgot)
>has as low a cross-section as a Neutrino.  So, if you time things
>right (BIG if, but this is sci-fi) You can shoot these through
>any type of armor.  Then they decay into a spray of ordinary 
>particles.
>
   Muons have a high penetration in matter, but not "as low a
cross-section as a neutrino" at reasonable energies. A muon interacts
electromagnetically so is easy to spot as a charged particle which has
managed to pass through two metres of steel and uranium in a particle
physics experiment. However, muons are just like other unstable
particles, they don't have some little timer inside which counts down to
detonation. They have a mean life, not an absolute life. If I generate a
beam of muons at some place and count the number of decays which occur in
each metre of distance from the generation point I will find that the
greatest number of decays occurs right in front of the generator, and the
farther I go the fewer decays I observe in a unit length. The total
number of particles which decays is obviously equal to the number
generated, and the 1/e length is a function of the time dilation of the
particles (assuming v close to 'c').
   So, let's say that the 1/e length is 'L' for my beam, the target is a
distance 'Z' away, and is 'T' metres thick. The number of muons which
decays within the target is:

1/L * int_{Z}^{Z+T} exp(-x/L) dx

   Now, let's pick some numbers for this. Let's say that L = Z (optimal)
and T = 1E-4 * Z. The number of decays within the target is 1/e * 1E-4, or
roughly 3E-5 of the input beam intensity. This is not very efficient. I
think that my estimate of 'T' is also a bit big for a realistic battle.

>Also imagine generating gravity-wave solitons.  (Self-reinforcing
>packets of waves.)
>
   Correct me if I'm wrong, but don't you need a dispersive medium (and,
in fact, an anomolously dispersive medium) to generate solitons? Current
theory holds that the speed of gravity waves in vacuum is independent of
their wavelength.


-- 
 Christopher Neufeld....Just a graduate student  | Don't let your mind
 neufeld@helios.physics.utoronto.ca    Ad astra  | wander -- it's too little
 utzoo.utoronto.ca!generic!cneufeld              | to be let out alone.
 "Don't edit reality for the sake of simplicity" |
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