Magnetic field topology and heat flux patterns under the influence of the dynamic ergodic divertor of the TEXTOR tokamak [Elektronische Ressource] / vorgelegt von Marcin Jakubowski

MAGNETIC FIELD TOPOLOGY AND HEAT FLUX PATTERNS UNDER THE INFLUENCE OF THE DYNAMIC ERGODIC DIVERTOR OF THE TEXTOR TOKAMAK DISSERTATION zur Erlangung des Grades eines Doktors der Naturwissenschaften an der Fakultät für Physik und Astronomie der Ruhr-Universität Bochum vorgelegt von Marcin Jakubowski aus Opole, Polen Jülich 2004 Referent: Prof. Dr. R. Wolf Korreferent: Prof. Dr. H. Soltwisch Dekan: Prof. Dr. R.-J. Dettmar Tag der mündlichen Prüfung: 23. Juni 2004 Abstract This thesis concerns the structures of the magnetic field induced by the Dynamic Ergodic Divertor (DED), which was recently installed at the TEXTOR tokamak in. Sixteen perturbation coils ergodize the field lines in the plasma edge and destroy the resonant surfaces. This creates an open chaotic system in the plasma edge. The structures of the magnetic field in the ergodic and the laminar region are systematically investigated using a set of codes, called “Atlas”. In Atlas, the field lines are traced using a mapping technique, which is based on the Hamiltonian formalism. This method is a fast and accurate algorithm to study the stochastic magnetic field lines. Typically, the ergodic region is a mixture of stochastic domains and island chains. The field lines in the stochastic domain have very long connection length and each field line fills the ergodic volume.