Study of Single Charged Particle Motion in a Toroidal System with a Three Dimensional Magnetic Axis

抄録

Four types of particle motions, namely, passing particle, blocked particle, untrapped banana and trapped banana are studied on the basis of analytical and computational methods in the drift approximation in a helical solenoid with low toroidicity. Computational results for trapped particles are in good agreement with those of theoretical predictions, when magnetic field configuration has a good helical symmetry, that is, αr₀∼1.0 and n>>1, where 2π⁄α and r₀ are the pitch and the radius of helical magnetic axis, respectively, and n is the pitch number of the system. In this case, the action is well conserved, especially for the trapped banana with small excursion along the axial direction.