knutsen@SRI-UNIX@sri-unix (12/06/82)
From: Andrew Knutsen <knutsen at SRI-UNIX> Someone just told me they'd heard about something called a railgun, which apparently is something like a magnetic linear mass driver but somehow involves using explosives to boost the field. Apparenlty its a one-shot device. Has anybody heard of this? Know where to find details? Tnx.
steve@BRL@sri-unix (12/07/82)
From: Stephen Wolff <steve@BRL> A conference on Electromagnetic Guns and Launchers was held in November, 1980; the proceedings of that Conference constitute the contents of IEEE Trans. on Magnetics, Vol MAG-18, Nr. 1 (January, 1982). The first paper in those Transactions discusses some work done here at the Army's Ballistic Research Laboratory. DARPA are still heavily involved.
York@MIT-MULTICS@sri-unix (12/07/82)
From: York at MIT-MULTICS (William M. York) Rail guns are a popular topic these days. I'm sure that there are many available references. Try any good science or engineering library. There have even been fairly extensive articles in Popular Science and the like. There are several different designs. The basic idea behind at least one of them is to take two parallel rails and connect them electrically with a piece of copper (for example). You then discharge a large capacitor bank through this circuit. The copper connector vaporizes, and the resulting plasma (still conducting) begins to travel "frictionlessly" down the rails due to the magnetic field, propelling a projectile in front of it. Simultaneously (for pratical purposes) you use an explosive to bring the "breach" ends of the rails together very rapidly. This raises the magnetic flux tremendously, increasing the acceleration dramatically. I believe that in some tests they have accelerated small lexan cubes up to escape velocity. Thinking about the energy of a small cube (of almost any mass) travelling at 11m/sec will show you why the military is interested. I'm sure that there are people on this list who can give you more detailed information. Have fun.
Jarrell.Advisor@M.PCO.LISD.HIS@sri-unix (12/08/82)
I saw an article a long time ago in newsweek I think. You might want to check the readers guide to periodical literature in your local library. Interesting little toy. Theoretically, it could be made to accelerate a small mass to near-lightspeed, atomizing whatever it hit. -Ron
steve@BRL@sri-unix (12/08/82)
From: Stephen Wolff <steve@BRL> "I believe that in some tests they have accelerated small lexan cubes up to escape velocity. Thinking about the energy of a small cube (of almost any mass) travelling at 11m/sec will show you why the military is interested." That's 11 Km/s, surely. Yes, that will show you why people might THINK the military is interested. Some military are however supremely **uninterested** in dragging great lumpy capacitor banks about your average battlefield, and there are already rather more direct methods for using explosives to accelerate projectiles of various sorts to quite high speeds.
davidson (12/10/82)
The rail gun works by accelerating a conductor between two rails which are conducting an enormous current. One approach to creating the current pulse is to compress a strong magnetic field with explosives. There was an article on rail guns and mass drivers in IEEE Spectrum earlier this year. Greg