Slab Model Analysis of Motion for a Charged Particle with Large Larmor Radius in Tokamak magnetic Field

The motion of a charged particle in tokamak magnetic field whose Larmor radius ρ₀ is not much smaller than the typical length L_B is studied in slab model by solving the equations of motion analytically, where L_B=|B/ΔB|. It is found that drift can still be predicted by the drift approximation, but gyration depends largely on the variation of the magnetic field over Larmor radius and the initial motion parameters. In the case of ρ₀/ L_B<<1, our results show their agreements with the previous work.