Re: magnetic lines like these ?

["Steven T. Ratliff" <str@nwc.edu>]

On 3/2/98 Ludwik Kowalski wrote:

[.............]
> How can a macroscopically neutral gas (ionized) be responsible for
> carrying lines of B around its paths?

I looked in some plasma physics books.  When the frequency of 
characteristic oscillations is low, and the conductivity is 
relatively large, then electrons and ions move together, and they 
move with the magnetic field lines.  The plasma behaves as if it is 
"frozen" to the field lines.    This applies to motion along B, as 
long as there are no steady electric fields along B.  Changes, or 
ripples, in B move at the same speed as the plasma.

Chen, "Introduction to Plasma Physics", p. 125:  "This concept of 
plasma frozen to lines of force and moving with them is a useful one 
for understanding many low-frequency plasma phenomena."

Steven Ratliff




Steven T. Ratliff
Associate Professor of Physics
Northwestern College
3003 Snelling Av. N.
Saint Paul, MN  55113-1598

Internet:  stratliff@nwc.edu (or str@nwc.edu)