抄録
Heat and particle flux control is one of the most important and difficult problems in steady state fusion devices. Dynamic Ergodic Divertor (DED) is the advanced concept that a rotational perturbed magnetic field is applied to make tokamak edge magnetic structure stochastic so that it may decrease the heat and particle flux onto the local target in the conventional divertor. This rotational perturbed field is created by two sets of local helical coils (LHC) with the phase difference of 90 degrees in supplied AC currents. For the DED experiment, it is important to know the perturbed magnetic field structure due to this coil currents. We obtain the mode structure of the rotating helical field using a new Fourier analysis so that we may improve the mode quality by employing a new coil configuration which has an addtional series of return windings so as to avoid unnecessary mode and decrease the coil self-inductance.
