The modelling of JET corner configurations, in which the strike points are positioned deep in the corners of the divertor, is extremely challenging for edge plasma fluid modelling tools. To circumvent this technical limitation, a geometrical approximation has been proposed, consisting in considering an artificial minor modification of the geometry of the divertor targets plates. In this paper, we investigate how significantly this approximation impacts the output of transport simulations. Using the SOLEDGE2D-EIRENE transport code which has the unique capability to be able to cope with both the full and the approximated geometry, we have performed a density scan in H-mode for pulses in which the outer strike-point lies in the corner of the divertor. We report here how simulations in the artificial geometry differ from the ones in unaltered geometry. At the exception of low density cases, mid-plane profiles in the closed field lines region and the near scrape-off layer are little impacted. Further out however, in flux-surfaces that are concerned by the geometrical modification, we find that modifying the geometry leads to a strong overestimate of the plasma density. The density perturbation is not local and concerns the whole flux surfaces. Although the divertor geometry is modified only on the outer side, the largest impact is found at the inner divertor where densities are systematically overestimated by a factor that can exceed 10 in low density cases in the far Scrape-Off Layer (SOL) and temperature underestimated by 10 to 20 eV in most of the studied density range. The near SOL and strike point peak values are also impacted in the same direction with density changes by a factor of 2. As a consequence, the threshold to detachment of the inner divertor is found lower in the approximate geometry than in the unaltered one. Due to the large flux expansion between the outer and the inner target, the difference in plasma is especially sensitive at the top of the inner divertor baffle, which could have consequence on the evaluation of physical sputtering at that critical location.

对于射流点位于偏滤器拐角深处的JET拐角配置进行建模，对于边缘等离子流体建模工具而言极具挑战性。为了避免这种技术限制，提出了一种几何近似方法，其中包括考虑对分流器靶板的几何形状进行人为的微小修改。在本文中，我们研究了这种近似对运输模拟输出的显着影响。使用SOLEDGE2D-EIRENE传输代码具有独特的能力，能够同时处理完整和近似的几何图形，我们在H模式下对脉冲进行了密度扫描，其中外部触击点位于脉冲的拐角处。转向器。我们在这里报告人造几何体中的模拟与未更改的几何体中的模拟有何不同。除低密度情况外，在封闭的磁力线区域和近刮层中的中平面轮廓几乎不会受到影响。但是，在更远的地方，在与几何修改有关的通量表面中，我们发现修改几何会导致对等离子体密度的强烈高估。密度扰动不是局部的，涉及整个通量表面。尽管偏滤器的几何形状仅在外侧进行了修改，但对内偏滤器的影响最大，在远隔层（SOL）的低密度情况下，密度被系统高估了一个可能超过10的因数，而温度却被低估了在大多数研究的密度范围内降低了10至20 eV。接近SOL和触击点峰值也会在同一方向受到影响，密度变化为2倍。结果，发现内部偏滤器的分离阈值在近似几何形状中比在未改变的几何形状中更低。由于外部和内部靶材之间的通量膨胀较大，等离子体的差异在内部分流器挡板的顶部尤为敏感，这可能会对在该关键位置进行物理溅射的评估产生影响。