3D MHD Equilibrium and Stability
Principal Investigator
Henry Gardner
Department of Computer Science,
Faculty of Engineering and Information Technology
For some decades there has been an international
scientific and engineering program to study the
containment of plasmas by toroidal magnetic fields with the aim of developing
a fusion power reactor. Australia presently makes a major contribution to
this program through the H-1NF Heliac which is a "stellarator"
experiment located at ANU and is funded through the Major National Research
Facility Program. Stellarators are an alternative to the better known "tokamak"
types of experiments but have the great advantage of not needing large currents
within the plasma in order to generate helical field lines. On the debit
side, the lack of axial symmetry of stellarators makes their theory more
complicated and simulation more computationally expensive than for tokamaks.
In particular, the simply nested magnetic surfaces found in tokamaks can
be broken and give rise to magnetic islands and regions of chaotic magnetic
field lines.
This project aims to simulate plasma equilibrium within H-1NF. The simulation
treats the plasma as a single conducting fluid which is a sufficiently accurate
approximation to find reasonable equilibrium solutions. A major part of
the study concentrates on understanding the growth of magnetic islands with
plasma pressure.
Co-Investigators
Sally Lloyd
Department of Theoretical Physics
Robert Dewar
Department of Theoretical Physics,
Research School of Physical Sciences and Engineering
David Singleton
ANUSF
Projects
k12 - VPP
What are the results to date and the future of the work?
Much of 1998 was spent studying the long-term convergence of the HINT code and analysing the effects of longitudinal currents in the plasma on the equilibrium characteristics. It turns out that the flat "rotational transform" profile of H-1NF makes it very susceptible to small longitudinal currents and considerable effort needs to be made to determine whether these are real effects or not. On the answer to this question, could hinge the determination or otherwise of island "self-healing" in H-1NF.