Radial structure of large-scale perturbations of the plasma in the T-10 tokamak

The emission from a tokamak plasma incorporates information on instabilities which are developing in the plasma. The variable components of the intensities of the soft x-ray emission and of the bremsstrahlung in the visible region which are coherent with oscillations of the m = 2 poloidal magnetic field have been measured in the T-10 tokamak. A method of synchronous detection was used to select the variable components. An interpretation of the results is offered. The radius of the q = 2 rational magnetic surface and the width of a magnetic island are found on the basis of this interpretation. Data on the radius of the q = 2 surface are compared with results calculated from the Spitzer formula, based on profiles of the electron temperature and effective charge of the plasma.