AI 中文总结
研究在EAST托卡马克上硼化壁条件下的I模式，通过与锂处理I模式对比，发现硼化能拓宽密度窗口、增加有利配置I模式，给出能量约束标度，表明其可拓宽EAST I模式运行空间，支持无ELM场景发展。
AI 中文摘要
I模式对于未来聚变反应堆是一种有前景的约束模式，因其结合了增强的能量约束、类L模式的粒子输运和自然无ELM运行。此前EAST的I模式研究仅在锂处理壁条件下进行。本文报告了EAST上硼化壁条件下I模式的首次系统实验研究，并与相同环向场（$B_t = 2.47$\,T）下现有的锂处理I模式数据库进行比较。硼化壁数据集显示出显著更宽的可及密度范围，格林沃尔德分数从$f_{\mathrm{GW}} = 0.26 - 0.77$，而锂化时为$f_{\mathrm{GW}} = 0.35 - 0.54$。更高的归一化$\mathrm{D}_\alpha$发射表明增强的边缘再循环可能有助于密度扩展。还观察到有利配置I模式显著增加：硼化壁放电中有$51\%$处于有利配置，而锂处理放电中仅为$8\%$。这些有利配置情况集中在高密度，具有更深的径向电场（$E_r$）阱和更强的$\mathbf{E_r}\times\mathbf{B}$速度剪切。当存在ETRO时，两种壁条件下电子和离子湍流之间的相关转变相似，尽管硼化时ETRO出现频率较低（$15\%$）。获得了固定$B_t$下的经验性EAST I模式能量约束标度，$\tau_E = 3.29 I_p^{0.51 \pm 0.10} P_{\mathrm{loss}}^{-0.53 \pm 0.05} \bar{n}_e^{0.08 \pm 0.07}$，表明功率降解比IPB98(y,2) H模式标度弱且密度依赖性弱。这些结果表明硼化可拓宽EAST I模式的运行空间并支持与反应堆相关的无ELM场景的发展。
英文摘要
I-mode is a promising confinement regime for future fusion reactors because it combines enhanced energy confinement with L-mode-like particle transport and naturally ELM-free operation. Previous EAST I-mode studies were performed exclusively under lithium-conditioned wall conditions. Here we report the first systematic experimental investigation of I-mode under boronized wall conditions on EAST and compare it with an existing lithium-conditioned I-mode database at the same toroidal field, $B_t = 2.47$\,T. The boronized-wall dataset exhibits a substantially broader accessible density range, with the Greenwald fraction extending from $f_{\mathrm{GW}} = 0.26 - 0.77$ , compared with $f_{\mathrm{GW}} = 0.35 - 0.54$ under lithiation. A higher normalized $\mathrm{D}_α$ emission suggests that enhanced edge recycling may contribute to this density extension. A striking increase in favorable-configuration I-mode is also observed: $51\%$ boronized-wall discharges are obtained in favorable-configuration, compared with only $8\%$ lithium-conditioned discharges. These favorable-configuration cases are concentrated at high density and exhibit a deeper radial electric-field($E_r$) well and stronger $\mathbf{E_r}\times\mathbf{B}$ velocity shear. When ETRO is present, the associated transition between electron and ion turbulence is similar under the two wall conditions, although ETRO occurs less frequently ($15\%$) under boronization. An empirical EAST I-mode energy confinement scaling at fixed $B_t$ is obtained, $τ_E = 3.29 I_p^{0.51 \pm 0.10} P_{\mathrm{loss}}^{-0.53 \pm 0.05} \bar{n}_e^{0.08 \pm 0.07}$, indicating weaker power degradation than IPB98(y,2) H-mode scaling and a weak density dependence. These results show that boronization can broaden the operational space of EAST I-mode and support the development of reactor-relevant ELM-free scenarios.
