Path: utzoo!attcan!uunet!snorkelwacker!apple!brutus.cs.uiuc.edu!psuvax1!rutgers!att!cbnews!military
From: oakhill!serval!seningen@cs.utexas.edu (Michael Seningen)
Newsgroups: sci.military
Subject: Re: mines
Message-ID: <11600@cbnews.ATT.COM>
Date: 21 Nov 89 04:20:38 GMT
References: <11549@cbnews.ATT.COM>
Sender: military@cbnews.ATT.COM
Organization: Motorola Inc., Austin, Texas
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From: oakhill!serval!seningen@cs.utexas.edu (Michael Seningen)
If my fields classes are still with me.  The hull of a sh
ip is such a sufficent cunductor plate for Electromagnet
ic waves that the magnetic field of the earth is altered
 due to the hull and therefore the mine can detect this 
change in magnetic flux and detonate.  
An interesting counter-measure was to run a wire or seri
es of wires around the hull (i'm not kidding) and set up
 an electric field of just the right value such that its
 corresponding magnetic field (which is 90 degrees wrt th
e electric field) that cancels the hull effect on the ear
ths magnetic field.

I know the general jist is right, my details and memory o
f fields (the nightmares are still there) are fuzzy.  May
be someone who taps this area more often than I can give 
a better explanation.

Mike Seningen
oakhill\!seningen\!serval