Finite Element Computations of Magnetic Field Perturbations in the NSTX Vacuum Region
Abstract
Finite Elements Methods were used to compute magnetic field perturbations due to tearing mode instabilities in the National Spherical Torus Experiment (NSTX.) Tearing mode instabilities caused by turbulence in the plasma force the magnetic fields in the vacuum region of the reactor. These instabilities can lead to a loss of confinement of the plasma. Understanding the mechanics of these instabilities is critical to designing a reactor resistant to this confinement-limiting factor. To detect these instabilities, perturbations in the magnetic field are measured and compared with computational simulation. Finite Element methods provide a method to simulate these instabilities. Ellipt2d software is used to solve equations of the Laplace and Helmholtz type in a region with a perfectly conducting wall geometry. The solution of the potential on the plasma boundary is then used in the PEST3 code for stability analysis. This method of directly measuring the magnetic field perturbations gives a better understanding of the dynamics behind tearing mode instabilities than previous measurement and analysis attempts.
- Publication:
-
APS Division of Plasma Physics Meeting Abstracts
- Pub Date:
- October 2003
- Bibcode:
- 2003APS..DPPGP1023G