Re: magnetic quenched triggered gap

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Ed Phillips <evp@xxxxxxxxxxx>

"Scot, all,

Yes, I have two 1.5" thk. x 4" dia. hockey puck sized N-48 neodymium
magnets that got stuck together and are now ONE 3" thk. x 4" dia. mag-
net!  Once they became "one" big magnet, I simply tightened a 4" hose
clamp around the seam where their surfaces meet, because I'm certainly
not going to be pulling these apart! As a matter of fact, these magnets
are DANGEROUSLY strong and can severely pinch any body parts
that happen to get caught between them (ask me how I know this) =^0
They can also chip off pieces of flying neodymium/iron shrapnel if two
of these magnets are allowed to fly into each other unimpeded.
It's not likely that the AC electromagnetic fields are going to
significantly
affect one of these types of rare earth magnets. The only thing you
really
have to watch for with neodymium magnets is heat. If they get much over
200*F, they start losing magentism and neodymium magnets have one
of the lowest Curie temperatures of permanent magnets. It seems to me
that bringing the magnets close enough to the spark gap contacts to ef-
fectively quench the plasma flux of the spark gap, while maintaining
ade-
quate thermal and electrical isolation from the SG contacts w/out the
be-
nefit of any cooling aids would prove to be a real design challenge.
IMHO, at least with higher powered systems, its more practical to just
utilize a rotary spark gap, with a possible seriesed forced air cooled
stationary gap to further commutate the heat of the spark.

David"

	David's advice about the temperature is important to note; these things
don't like to get very hot.  Solution to this problem is to embed them
in a suitable magnetic circuit (plain old cold-rolled steel would be
fine) with suitable pole pieces where the spark is to occur; the field
would be oriented perpendicular to the direction of the spark.  The
question of interest would be is does the magnetic field do anything
useful.  I've thought of making such a device but would rather see the
results of someone else's measurements and experiments first.

	As an aside, I doubt that the hose clamp is really necessary.  Those
things are now together for all eternity unless someone goes through
some real heroics!

Ed