The interaction between plasmas and magnetic fields


Reference is first Principles of Electrical Engineering by C.  H. W.  Biggs about 1890

Some photos  added by K1 UGM


 Suppose Fig. 25 to represent a

portion of wire forming part of a conductive circuit

through which a current is passing.  If we take a sheet.

of paper or glass, and lightly sprinkle iron filings upon

the plate of glass we shall find that the filings will

arrange themselves somewhat concentrically around

the wire—that is, we find some force acting upon the

filings, causing them to assume the ring shape. 





 We may say that the position of each ring of filings iss

determined by a force acting in a certain direction, or

forces acting in certain directions.   It is clear that

the force or forces start somehow from the conductor,

total space through which the lines of force act as the "field of force." 





An example of this force is shown below

Substituting an arc discharge for the wire and bringing a magnet

close to it, distorts the  magnetic field lines on one side of the discharge
 more than the other thus  forcing the discharge closer to one side of the
 arc tube than the other. Its an interesting  demonstration of  the very powerful
 interaction between plasmas and the surrounding magnetic fields

 It should be remembered that these plasmas generate magnetic fields of their own


Magnetic Circuit. Around  Horseshoe Magnet
The longer the air space to be
traversed by the lines of force
 the greater the resistance, so for most practical purposes the iron or steel
part of the circuit is bent so as to bring the ends or
poles as near together as possible and reduce the air



                         FIG. 29..

space to be traversed by the lines of force.  Fig. 29

shows an ordinary form of magnet.