Calculation of power deposition patterns on the ergodic divertor

Energy deposition on the vented target plate of the ergodic divertor is analyzed. Shadowing is shown to depend on short parallel excursions. Short excursions also determine the radial penetration of the flux tubes and hence the poloidal phase of the field line with the magnetic perturbation. The latter feature is shown to govern the energy deposition patterns. A WKB calculation allows one to relate the field line radial excursion to the deposited energy flux. The good agreement between the experimental results and the model demonstrates that the calculation yields a comprehensive procedure to simulate power fluxes to all parts of the first wall.