Internal magnetic field measurements in tokamaks
The functioning of tokamak devices relies on externally induced plasma currents which serve the two-fold purpose of heating the plasma and creating an appropriate magnetic field structure for confinement. Hence, a detailed knowledge of the current distribution and its dependence on the operational conditions is important for both the theoretical understanding and the practical improvement of tokamaks. This contribution reviews the experimental techniques for measuring the current density profile or the associated magnetic fields within the plasma. Starting with a brief description of the equilibrium magnetic field structure in toroidal geometry and a short account of indirect and passive diagnostic methods, an assessment is made of the currently available techniques which involve the use of photon or particle beam probes. In particular, methods based on Faraday rotation, Zeeman splitting and motional Stark effect are examined, and their potential and limitations are illustrated by measurements on existing tokamaks.
Bibliographic Reference: Article: Diagnostics for Contemporary Fusion Experiments (1991) pp. 37-55
Record Number: 199211077 / Last updated on: 1994-11-29
Original language: en
Available languages: en