The divertor concept and the divertor materials envisaged for ITER FEAT restrict the maximum values of the stationary and transient heat fluxes. The maximum stationary heat flux is limited by the active cooling structure. The limit for transient events is given by the maximum tolerable surface temperature. This paper will review different options for divertor heat flux reduction. Proper geometric orientation of the divertor targets reduces the heat flux to the target plates at most by a factor of 60 relative to the parallel heat flux determined by upstream transport. The radiation capability of closed divertor configurations is doubled compared to open configurations. A further reduction of maximum heat load can be achieved by increasing the wetted area in double-null plasma configurations. The energy transported by transient events (type I ELMS) is up to 30% of the total energy deposited in the divertor. The heat flux profile during ELMS is not significantly broadened and is comparable to the profile between ELMS. The duration of the energy deposition varies with edge plasma parameters between 0.1 and 1 ms. The expected transient heat flux for ITER FEAT conditions is above the tolerable value. This requires the further development of operation scenarios with tolerable ELMS (e.g. type 11) preserving the high energy confinement of type I ELM scenarios. [References: 43]
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机译：ITER FEAT设想的偏滤器概念和偏滤器材料限制了固定和瞬时热通量的最大值。最大静止热通量受主动冷却结构限制。瞬态事件的极限由最大容许表面温度给出。本文将探讨减少偏滤器热通量的不同选择。相对于上游输送所确定的平行热通量，分流器靶材的正确几何定向最多可将至靶板的热通量减少60倍。与开放式配置相比，封闭式分流器配置的辐射能力提高了一倍。通过增加双零等离子体配置中的浸润面积，可以进一步降低最大热负荷。瞬态事件传输的能量（I型ELMS）最多占分流器中总能量的30％。 ELMS期间的热通量分布没有显着拓宽，可与ELMS之间的分布相媲美。能量沉积的持续时间随边缘等离子体参数在0.1到1 ms之间变化。 ITER FEAT条件下的预期瞬态热通量高于容许值。这就需要用可容忍的ELMS（例如11型）进一步开发操作方案，同时保留I型ELM方案的高能量限制。 [参考：43]
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