# Crushing a magnetic field

What would happen if you crushed a magnetic field to an ever decreasing size?

Thanks.

EDIT:

How small could the field possibly go? Is there a limit on how small it could get?

Is there a maximum field density based on the size?

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It would get smaller. – Dale May 24 '12 at 17:46
and the field density would increase :-) – Rory Alsop May 24 '12 at 17:47
I would suggest to add a "mumbo-jumbo" tag. – yohBS May 24 '12 at 17:52
Fields can't move, so you can't crush them--- they are at fixed points. You should ask "what happens if I concentrate a given amount of field energy in a smaller and smaller region in a stronger and stronger magnetic field". This can't happen by crushing, and in fact, it is hard to see how to do it: you need a smaller and smaller solenoid. Without the precise setup, the question is not clear. Are you asking "what happens if you squeeze a static magnetic field into a region which is very small in all dimensions?" This is impossible by zero divergence. – Ron Maimon May 24 '12 at 18:20
@Ben yohBS is kind of making a valid point, though - it's not really clear what you mean by crushing a magnetic field, given that it's not a solid physical object and that it doesn't have a size (it fills all of space). Could you edit your question further to clarify what you mean? – David Z May 24 '12 at 19:39

It is theoretically possible to generate very high magnetic fields (tens of millions of oersteds) with rapid squeezing conductive shells covering the magnetic flux.

Sufficiently rapid compression of shells can be achieved with cumulative directional blast.

The converging detonation wave then produces plastic compression and deformation of the conductive cylinder or other type of massive loop covering the magnetic flux.

The principle is that the explosive energy goes into the energy magnetic field, produced by eddy currents flowing in the compressible conducting shell. I remember we did a relatively simple calculation in a lecture.

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The wikipedia page for these devices is Explosively pumped flux compression generators.They have been developped from the early 1950s as electromagnetic weapons. – Frédéric Grosshans May 25 '12 at 13:49
@FrédéricGrosshans Thanks for this link. – Martin Gales May 26 '12 at 7:01