We report the first in-depth comparison of the impact of toroidal magnetic field direction on solid boron injection used for Edge-Localized Mode (ELM) control, power exhaust, and core high-Z impurity control in the Experimental Advanced Superconducting Tokamak. With favorable ion ∇B drift towards the upper X-point in an upper-single-null configuration, boron injection effectively suppresses ELMs, produces a detachment of the inner divertor target, and leads to improved energy confinement. ELM suppression in this configuration is accompanied by the excitation of an Edge Harmonic Mode. In contrast, with unfavorable ion ∇B drift away from the upper X-point, boron injection also suppresses ELMs but leads to a more symmetric detachment state of both the inner and outer divertor targets, while plasma energy confinement is slightly degraded despite similar boron injection levels; a different low-frequency coherent mode without multiple harmonics is observed. Measurements from toroidally separated views show that the divertor response to boron injection is essentially toroidally symmetric, supporting the use of two-dimensional SOLPS-ITER modeling with a toroidally uniform impurity source. These experimental observations are qualitatively consistent with SOLPS-ITER simulations, which highlight the critical role of E × B drift effects in setting the Bt-dependent in–out asymmetry of detachment and in asymmetrically transporting particles and injected impurities within the scrape-off layer and private-flux region. These findings underscore the importance of drift physics and real-time wall conditioning in controlling low-Z impurity transport and optimizing edge solutions for integrated, ELM-stable, high-performance tokamak operation.
我々は、実験型先進超伝導トカマクにおけるELM制御、パワー排気、およびコア高Z不純物制御に使用される固体ホウ素入射に対するトロイダル磁場方向の影響の最初の詳細な比較を報告する。上側シングルヌル配位においてイオン∇Bドリフトが上側X点に向かう好ましい方向では、ホウ素入射はELMを効果的に抑制し、内側ダイバータ板のデタッチメントを生じさせ、エネルギー閉じ込めの改善をもたらす。この配位におけるELM抑制は、エッジ高調波モードの励起を伴う。対照的に、イオン∇Bドリフトが上側X点から離れる好ましくない方向では、ホウ素入射はELMも抑制するが、内側および外側ダイバータ板の両方のより対称的なデタッチメント状態をもたらす一方、同様のホウ素入射量にもかかわらずプラズマエネルギー閉じ込めはわずかに劣化し、複数の高調波を伴わない異なる低周波コヒーレントモードが観測される。トロイダル方向に分離された視野からの測定は、ホウ素入射に対するダイバータ応答が本質的にトロイダル対称である