Resonant conductor configurations for a magnetic limiter in TEXTOR

Conductor configurations generating a radially disturbing magnetic field resonant to the q = 4 flux surface of the TEXTOR plasma are considered. The Fourier spectrum of the magnetic field of the 'near plasma' configurations is characterized by one dominant Fourier component ( m = 4, n = 1). These configurations are based essentially on helical windings with the same pitch angle as the field lines of the resonant flux surface. The 'far plasma' configurations, consisting of long or horeseshoe-like solenoids, generate uni-directional magnetic fluxes at each end of the solenoid and thus avoid the unfavourable dipole fields of the near plasma configuration. Besides the dominant Fourier component (m = 4, n = 1), the component m = 3 and n = 1 also appears, if the solenoids at the inner side of the torus are omitted for engineering reasons. (orig.)