Experimental measurements of energy confinement time in fusion plasmas

Experimental measurements of the energy confinement time in fusion plasmas

A thermonuclear fusion device in the reversed field pinch (RFP) configuration is operated at the Alfvén Laboratory, KTH, Stockholm (Sweden). The device, denominated EXTRAP T2R, is part of the international programme on fusion research sponsored by EURATOM. The EXTRAP T2R group has strong international collaborations with the other three RFPs experiments operating in the world: MST in Madison, Wisconsin (US), RFX in Padova (Italy) and TPE-RX in Tsukuba (Japan). The EXTRAP T2R group consists of approximately twenty persons including researchers, PhD students and technicians. One of the goals of the EXTRAP T2R research is the study of the plasma confinement properties.

The plasma confinement properties are characterised by the so-called energy confinement time that expresses the ratio between the plasma energy content and the input power. Part of the plasma energy content is dissipated by resistive instabilities. The importance of the energy resistive dissipation is determined by the Lundquist number S. Estimates of the energy confinement time and of S are based on the experimental measurement of several plasma quantities such as the plasma electron density, the plasma effective charge, the electron temperature and the ion temperature.

The plasma energy confinement time is measured in EXTRAP T2R using several diagnostics including: an interferometer, which provides the electron density, a laser scattering system, which gives the electron temperature on axis, and a neutral particle energy analyser for the ion temperature on axis.

A project on experimental measurement of the energy confinement time in EXTRAP T2R is available. The aim of the project is to extend previous studies of the energy confinement time scaling with S. The project involves using several diagnostics to measure different plasma quantities, taking part in the experimental campaigns of EXTRAP T2R and data acquisition and analysis. For these reasons the project will be carried out at the Alfvén Laboratory.

A suitable candidate for this project would be a student with basic knowledge of plasma physics and interested in experimental physics. Knowledge of one (or more) of the following scientific software is desirable: IDL, MatLab, Mathematica, MathCad, Origin and Fortran.