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Spheromak Equilibrium Studies
Immediately following formation, the Spheromak is not in an equilibrium
state: the field and pressure profiles imposed by the gun are unstable.
After formation, the fact that the plasma is a resistive (not perfect)
conductor allows the fields embedded in it at startup to 'relax' to a state
of lower energy. The resistivity of the plasma means oscillations will
be damped, so that the relaxation will tend towards a steady state, or
equilibrium between the forces of plasma pressure and magnetic field.
Experiments on SSX over the last year have explored this equilibrium
state and the form it takes. A time-resolved fit of models to data determined
which theoretical models best fit the data at successive time steps, and
whether the spheromak evolved over its lifetime. This gave an indication
of the importance of various forces in the determining the equilibrium.
Data seem to indicate that the predominant factor is current distribution,
in accordance with a nonconstant-lambda force free model with small pressure
For more detailed results and more explanation, please refer to one
or all of the following (level of physics indicated for each):
This project is now concluded, and reconnection experiments are underway.
Download a technical paper on the topic as postscript
(3.6MB) or PDF (735KB) for a
concise (and somewhat technical) discussion of both formation and equilibrium
Download my thesis as postscript
(3.6MB) or PDF (735KB)
for the most comprehensive explanation of our project. Also written for
a general physics audience.
APS Poster from Nov. 1996 gives
a good intro to the project along with tentative conclusions/data. Written
for plasma physics audience.
Thesis Talk from April 1997 presents
the most recent data and interpretations, but is brief. Because these viewgraphs
are intended for a talk, it is missing some of the explanatory wording.
For a general/undergrad physics audience. Reading this and the poster is
a good intro.
Geddes / 180796 / email@example.com