AN EXPERIMENTAL-STUDY OF MAGNETIC ISLANDS AS HAMILTONIAN-SYSTEMS

Magnetic islands play an important role in determining plasma transpor t in toroidal magnetic confinement systems. The magnetic error fields and the associated islands can be theoretically described by a Hamilto nian approach. Experiments have been conducted on the Compact Auburn T orsatron [Fusion Technol. 18, 281 (1990)] to test the applicability an d limits of the first-order Hamiltonian theory to magnetic islands. A novel set of helical trim coils with the same spatial periodicity as a n tau = 1/2 magnetic island were used to create a perturbation field o f variable magnitude and phase. Extensive experimental parametric stud ies of the magnetic island were conducted and compared with theory. It was found that the first-order Hamiltonian theory is applicable for t he complete range of experimental error fields.