Beta Limit for a System with a Closed Helical Magnetic Axis

抄録

The “critical β” at which an equilibrium either ceases to exist or becomes poor for confinement is determined for a non-axisymmetric system with a closed helical magnetic axis. The plasma is assumed to have a circular cross section through which a longitudinal current with a flat radial profile flows in a direction to either increase or decrease the rotational transform of the magnetic field. It is shown that an equilibrium does not exist in a certain range of current which increases the rotational transform due to the resonance of toroidal effects. It is also shown that there are the upper and lower limits of β value for a stable equilibrium.