Parallel closures in an inhomogeneous magnetic field

We solve a reduced drift kinetic equation with a Krook-type model collision operator to obtain parallel closures. Grid points in the velocity space are chosen for Gauss-Laguerre quadrature to take closure moments. For trapped and passing regimes, analytical solutions are expressed as kernel-weighted integrals of thermodynamic drives. The analytical sloutions are compared to numerical solutions obtained from a finite difference method. Inverting the free streaming operator near a bouncing point is investigated to improve accuracy of solutions.