Pitch-Modulated l=1 Torsatron

Abstract

The pitch modulation on an l=1 torsatron field leads to the improvement of the confinement properties due to the formation of a local magnetic well, the reduction of the field ripple and the increase of the rotational transform. The pitch-modulated l=1 torsatron has the simplest coil structure and generates a compact helical magnetic axis configuration with a much smaller excursion amplitude than the coil radius. Here, the vacuum configuration and the finite beta equilibrium of this system are described.