From: djwj <djwj@e...>
Date: Fri, 4 Jun 1999 15:51:05 -0600
Subject: Re: Railgun
Okay I'm going to try One more time. I think I can be understood this time.
Once upon a time in the Real World...
The Railgun, from the "military" perspective is a misnomer. From the
scientific perspective a gun is any form of "matter projector" from a pop gun
to a supercollider. This matter may be anything from a five ton boulder to one
electron or less. It does not mean that it has any real military value.
The *BASIC* Railgun, the scientific device, comprises two rails from one to
three feet in length, one capacitor of one to twenty Farads, not microfarad
capacitors used in electronics, and a spool of common copper wire, cut into
strips long enough to reach between the rails. Drop the wire on the rails
completing the circut, the wire is vaporised, the rails are magnetised, and
the plasma state wire is sent off along the axis of the gun. This device has
no military value, This is what is called a Rail Gun, Rail for the two
stainless steel rails, gun for "matter projector".
The Rail Gun is a scientific device used for studying the effects of plasma, a
state of matter with properties similar to energy, when it collides with
other substances. Between twenty and thirty-five years ago: one
theorised use of such research may have been to create some sort of "matter
/energy"
transmission. If you can find a substance that will conduct plasma like
energy, not be anniahalated when it hits it like matter, you can transmit
matter "as energy", and we'll get around to rebuilding the object when we can
get it there. Rember much of the "Academic" research at the early and middle
part of the atomic age was trying to figure out how to accomplish all
those marvelous technologies that appeared in "pulp" sci-fi, not on the
effects of rock-and-roll on fruit flies or wether salsa is a vegetable.
Of course no substance has been found that can "conduct" plasma and such
research was (publicly) abandoned (nah, I don't believe in *FNORD*).
The Railgun was the orphan child of this research, and was left to demented
engineering students to do with as they will. One such demented engineering
student, his identity lost to the mists of time (or a research archive
somewhere) noticed similarities between the plasma in a railgun and the
propellant of a chem.slugthrower. Both expanded along the axis of the device,
the gunpowder contained by the barrel and the plasma contained by the magnetic
field. The plasma has three important advantages over gunpowder. The
difference between the temprature of the air and the temprature of a gunpowder
"burn" versus the difference between the temprature of plasma and the
temprature of the surrounding air meant that the plasma had more force, more
"desire", to move to a state of equilibrium with the environment, the upshot
of which was the plasma expands faster, able to impart more kinetic energy to
a "slug" (penetrator rod, whatever). The second advantage was that the Railgun
"pushes" the plasma "event" (meaning "all the interesting stuff", for our
purpouses this means burn or explosion) forward, where a gunpowder "event" has
a "static" location in the gun. The movement of the plasma event adds that
more kinetic energy to our slug. The final and important advantage was with
regards to our friend Issac Newton. The copper wire that is used as the
propellant has negligeable weight when compared to the weight of the entire
assembally. Throwing the plasma made up of the wire forward has such a
negligeable effect on the gun that "Felt Recoil" the important bit, was
negligeable. The fact that the plasma was moving forward at a similar rate to
it's expansion meant that the gun itself never got the kick from the plasma
expansion. The entire effect was more like a rocket or an "Orion Engine" than
like a traditional gun. So conservation of energy askes how does this move a
slug? The energy comes from the capacitor moving the plasma in a similar
manner to a mass driver cannon, rember that a capacitor big enough to propell
a slug of military value can kill an entire herd of cattle standing in inch
deep water.
Now for the problems which the soultions are probably still classified, rember
the railgun "Ignition system" has been around for a long time.
How do you keep the plasma from overtaking the round How do you keep the
plasma from destroying the round How can you get the rate of fire up to
respectable levels (The chief problem here being that you have to charge
enormous capacitor banks to make this thing work)
******
Okay so the military uses the term Railgun to refer to the final Hypervelocity
Penetrator Round version of this device, Why should we as
Sci-Fi gamers care differently. Answer: The Railgun is an ancestor that
can have many different descendants, not just the plasma propelled HKP
thrower. The railgun system can use the plasma itself as a projectile in
multiple ways. The Thrust Nozzle I have heard about, Oerjan Ohlson pointed out
a lot of defencies in that system, My response is that we need those demented
engineering students to figure out the answers to those problems, not just
say it can't be done. My dad was one of those demented geo-magnetists
that
was trying to garage-build (Dorm-build?) a device to prove that it could
be done, and, on accident, took out his own stereo system with it. Plasma
physics can be studied by hitting a quantity of plasma with pulses from
microwave emitters, the process sets the plasma up in orbits that generates
magnetic fields which contain the plasma in those orbits, moving this ball
becomes a tricky proposition as anything that touches it will be anniahlated.
This has been done for more than twenty years. Theoretically if you have a
"Ball" of plasma that already has a kinetic motion, say fired from a railgun,
and you hit it just as it clears the rails with the microwave pulse emitters,
you can have a VERY long range weapon, as the plasma will remain stable for
better than the length of the gun to the horizon, possibly even as a surface
to orbit planetary defence system. If we pidgeonhole the railgun as simply a
method of delivering HKP rounds, other methods of inquiry may be closed to us
later. To wit: The "Year 2000 Bug" was a result not of any one person's
failure, but the tendency to say "It's always been that way, why change it?".
Even when the CMOS was sufficient to handle SIXTEEN digits for the date, "It
had always been two digits. We can use that storage for something else." Now
were
scrambling to fix the problem before being catapulted back en-masse to
the year 1900 to do it all over again until we get it right.
Railguns, computer CMOS, and future choices: what's the connection?
As a Sci-Fi junkie myself I recognize that in some way all of us as
Sci-Fi fanatics are responsible for keeping the dream alive, *ANY* dream
from space travel, to replicators for all. Even weapons have their place in
that heritage: without the German V2 missile we could have never gone to the
moon, much less have had satelite T.V., Global positioning systems to improve
everything from archaeology to farming, non stick cookware, the personal
computer you are reading this on is a decendant of a machine of war. We may
not be able to recognise the repricussions of the weapons we build today, but
who knows? A Railgun ignited plasma drive may be the key to FTL travel, or a
controlled plasma bust cure cancer. How? Don't ask me, I'm just the dreamer.
Science Fiction, and those of us that participate in it, in any way, are an
integral part of modern progress, and even progress throught the centuries.
We, the dreamers, the wishers, the thinkers, we ask questions that simply come
to us "What if I could...?" or "I want....". The demented engineering students
ask themselves "How can I build that?". Even the mundanes and skeptics have
their place. Nothing in the world is quite as powerfull to our species as the
challenge in proving the statement "It can't be done." wrong.
******
Sorry if I became too philosophical for this list but it's important to me.
When I was young I dreamed of becoming a Xeno-Geologist, At the time I
said I wanted to study moon and mars rocks. I rember when school stopped for a
shuttle launch. Every T.V avalable was placed around the school, and classes
were herded to within sight of them. I rember the first day this didn't happen
was the day the Challenger exploded. Then it seemed sadly prophetic in a way.
It still does.