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Re: Magnetazation of Toroid

>Message-ID: <199608080225.UAA01860-at-poodle.pupman-dot-com>
>Date: Wed, 7 Aug 1996 20:25:40 -0600
>From: Tesla List <tesla-at-poodle.pupman-dot-com>
>Subject: Re: Magnetazation of Toroid

>From huffman-at-d0tokensun.fnal.govWed Aug  7 19:14:18 1996
>Date: Wed, 7 Aug 96 08:09:38 CDT
>From: Dave Huffman <huffman-at-d0tokensun.fnal.gov>
>To: tesla-at-pupman-dot-com
>
>
>Hi Skip & All,
>I have tried a super magnet to deflect the 'arcs' with no apparent
>effect. Since the current is very small, so is the force exerted.

   At TRIUMF, charged particles and magnetic fields are our existence.
   This is also true of your lab, Fermi National Accelerator Laboratory.

   I shall talk about the accelerated electron, but the same concepts
   apply to all charged particles.

   You I believe you have made a slight error in your thinking.  The
   force felt by an electron experiencing a given magnetic field has
   nothing to do with the presence of other electrons feeling the same
   field.  If the beam current gets so intense so that via its own
   magnetic field it actually interferes with the incident magnetic
   field, then there is an effect.  But to create such a field strong
   enough to be comparable to the hand-held ferrite magnets, this will
   be at beam currents of several amps or several 10's of amps, not
   microamps or milliamps.  So the influence of a magnetic field on a
   beam of electrons is not affected to any great degree by the
   amplitude of a low-intensity beam such as the streamers from a
   Tesla Coil.  What the degree of bending *is* affected by is of
   course the *energy* of each electron.  The more accelerating
   voltage behind (or in front of) the electron, the greater will the
   energy gain be in a given distance, and the more difficult it is to
   deflect magnetically at right angles to the direction of the
   electrostatic acceleration.  Thus the "stiffness" of an electron
   beam, or any charged particle beam, has to do with the energy and
   the mass of the idividual particles, not really the *number* of
   particles (and current is the number of singly-charged particles
   per second).  This effect is typically often seen in TV's and
   computer screens where the screen HV regulation is poor.  A change
   in brightness produces a change in  the screen high-voltage, and
   the picture blooms (gets bigger) when it gets bright as the beam
   current increases and the accelerating screen voltage falls (by
   beam loading) making the more intense beam easier to deflect by the
   deflection coils;  the picture shrinks when it gets dark because
   the screen HV goes up making the less intense electron beam stiffer
   and more difficult to bend.

   In a gas arc over a certain range of currents, the larger currents
   are more easily deflected because the accelerating voltage is less
   in an intense arc due to the negative-resistance characteristic of
   arcs.  Strange as it seems, within this range, lower-intensity arcs
   have a higher voltage across them than more intense arcs.

>Large currents, arc welder, are readly influenced by strong magnets.
>(rail guns)

   This is mostly not due to negative-resistance effects, nor
   intensity effects, but simply because of the low accelerating
   voltages.  The *energy* of the individual charged particles
   (hundreds of electon-volts) is low by orders of magnitude when
   compared to the discharge from a Tesla Coil with millions of volts
   to accelerate the electrons.


>Tesla did discover that under certain conditions some discharges
>became extremely sensitive to magnetic fields. He suggested that 
>information could be sent this way. 
>BTW a super magnet will cause a dark spot in a florescent lamp.

>Could a very strong field 'quench' a florescent lamp?

   Yes. A field which would deflect the current at right angles to its
   normal flow that thus deflect it into the glass.  Or, a strong
   magnetic field right along the axis of the flourescent tube should
   be able to cause the electrons and gas ions to travel in a tight
   (constricted) spiral down the inside of the tube rather than at the
   edge near the glass.  Current density at spots on the filaments
   would become rather high.  We had an ion source we used for about
   20 years that worked this way (the Ehlers Source).  The arc chamber
   was only a couple of inches long, though, and the gas was hydrogen.
   Now we use a 'cusp' source.  A ring of *intense* permanent magnets
   produces magnetic fields with sharp cusps in a hydrogen plasma,
   which help to maintain and focus an intense ion beam.

   Either this focussing effect of a cylindrical ring of magnets or
   the solenoid effect, (in the beam business known as an "Einzel
   lens") makes me think it might be interesting to try something like
   this cylindrical ring of magnets on top of a Tesla Coil.  If the
   discharges could be made to begin at the center of (and inside)
   this cylinder and then travel lengthwise down the cylinder and
   parallel to the internal magnetic field inside the cylinder, I have
   the definite feeling that a person should be able to exert some
   small degree of control and focus the discharges from the TC top
   end, even though they are AC discharges.  I don't know if this has
   ever been tried on air arcs.  It works fine in vacuum.

>Dave

  All the best,

 Fred W. Bach ,    Operations Group        | Internet: music-at-triumf.ca
 TRIUMF (TRI-University Meson Facility)    | Voice:  604-222-1047 loc 6327/7333
 4004 WESBROOK MALL, UBC CAMPUS            | FAX:    604-222-1074
 University of British Columbia, Vancouver, B.C., CANADA   V6T 2A3
 "Accuracy is important. Details can mean the difference between life & death."
 These are my opinions, which should ONLY make you read, think, and question.
 They do NOT necessarily reflect the views of my employer or fellow workers.