Determination of rational surface position and magnetic island width from electron cyclotron emission (ECE) radiometry in TCABR

Measurements of the electron temperature radial profile T_e(r) have been performed on the Tokamak Chauffage Alfve´n Bre´silien tokamak with high radial resolution, using an electron cyclotron emission radiometer. The temperature profile shows distinct peculiarities in discrete radial regions which can be associated with the presence of magnetic islands. A method is proposed here to determine the radial positions and widths of the magnetic islands based upon measurement of the Fitzpatrick kind, not completely flattened, radial profile of the electron temperature T_e(r). In combination with other well-known methods, the suggested methods can give additional possibilities for comparing experimental and theoretical results in the study of magnetic islands.