A simple method is proposed to determine the equilibrium quantities (such as the plasma position and Shafranov's parameter Lambda ) in Tokamaks and RFPs. This method is available in the transient phase of a discharge, in which the plasma equilibrium is maintained by time-varying vertical fields, e.g. in the case where the plasma is surrounded by a thin shell. In this method, the external fields measured are matched to the approximate solution of the Grad-Shafranov equation in a vacuum by a fitting procedure. In the case of a circular plasma boundary, only a small number (>or=6) of the field measurements can provide a stable and rapid determination of equilibrium. A successful application to the REPUTE-1 RFP plasma with thin shell reveals that in most cases the plasma starts to move outward and downward before the plasma current begins to fall.
All Science Journal Classification (ASJC) codes
- Nuclear Energy and Engineering
- Condensed Matter Physics