A three-dimensional analytic model for discrete limiters in ITER

摘要

It is foreseen that ITER will employ a number of discrete limiters for the start-up and ramp-down phases of each discharge as well as for protection of the main wall during the diverted phase. Predictions are required of the radial power e-folding length, λ_q, in order to estimate the power loading on the limiters. This 3D problem has been addressed by Kobayashi et al (2007 Nucl. Fusion 47 61-73) using a numerical edge code, EMC3-EIRENE. An analytic 3D model is presented here which well approximates the code calculations of λ~q, providing simple and convenient expressions for λ_q in terms of the shape and number of discrete limiters.