Ordered hierarchy of kinetic equations in the divertor ordering

Ordered hierarchies of kinetic equations are developed for the conditions in which the radial gradient scale length is only about 10 times larger than the poloidal gyroradius and in which the ion-ion Coulomb scattering rate is only about 10 times larger than the ion-impurity and ion-neutral scattering rate; such conditions being representative of a tokamak divertor plasma. Conservation of particles, momentum and energy are incorporated into the kinetic equations. These equations provide a starting point for the investigation of phenomena on the transport time scale in the scrape-off layer and divertor channel of tokamaks