Toroidal Multipole Research Articles

Average Minimum Heliotron Magnetic.Field with Inner Ring Conductors

A magnetic field having an average Minimum B configuration can Be produced by immersing the negative coils of the heliotron field in the plasma. Assuming the sheet current model, the general expression of this magnetic field is deduced. Some of the field : properties such as the effect of the position of the neutral lines are discussed.In this Configuration, the neutral lines, on which the magnetic field intensity is zero, encircle the minor axis of the torus, while they encircle the major axis in the case of the toroidal multipole. The separatrix is farmed by the field lines which cross the neutral lines, and the bottom of th6.mane.tic well is on the separatrix. The equivalent potential, U=-_??_dl/B, increases monotonically from the separatrix towords the wall of the vacuum vessel, so that the plasma injection into the well may Be easily attained. Besides, the potential in the : region near the wall is higher than that on the magnetic axis.