I'm a little confused about how the intended motion of particles in a
tokamak would be created.  My question is, how is the motion along the
cylindrical axis get induced?  Do the external currents used to create
the currents in the plasma have to be time varying?  The reason I ask
is b/c it seems to me that a reactor could run indefinitely only if
the currents outside the tokamak increase indefinitely... running into
a significant engineering problem.  In other words, (in Maxwell's
equations) j must vary in order for the curl of B to vary in order to
have a time variation of B, and therefore an induced curl of E.  Am I
missing something here?  Or is there some other way that the particles
in a plasma are propelled along the tokomak's axis (ionic injector
beam or induced drift speed e.g.)?  Thanks

How would you like
		'all of the above'
	as an answer?


There are many ways of inducing rotation in the tokamak,
  rf (radio-frequency)  induced heating is common"
http://fusion.gat.com/theory/rf_heating/rf_heating.pdf

  There are others. Here is a quote from General Atomics:
        ".. In addition to neutral beam
injection, other means of rotation generation such as RF-power injection is of
great interest  .."
http://web.gat.com/theory/rf_heating/rf_heating.pdf

   The answer to:

               Do the external currents used to create
the currents in the plasma have to be time varying?

is "Yes".  Tokamak works a bit  like a cyclotron  - field
changes with time.

   I do not see the logic behind:


 "   a reactor could run indefinitely only if
the currents outside the tokamak increase indefinitely     .."

  It is a periodic variation.

To apply Maxwell eq. directly to the tokamak theory is not
a good approach. They do apply - but lot of work was done
to create magnetohydrodynamic equations and methods of solution
and approximations which may work.

It may be a good idea to pick a specific project and do more reading.


Tutorial
           http://hif.lbl.gov/tutorial/tutorial.html
project
            http://www.plasma.ernet.in/aboutsst1.html