Access to steady-state (SS) plasma scenarios that can be potentially achieved in ITER by the exploitation of the neutral beam (NB) and electron cyclotron (EC) heating and current drive capabilities, including their foreseen upgrades, has been assessed and development of the Q ∼ 5 ITER SS operation (SSO) scenario has been carried out by combining all the necessary physics and engineering components. A set of modelling codes including 0.5D/1.5D transport and source modelling suites (METIS, ASTRA and CORSICA) and ideal MHD stability analysis codes (KINX and MISHKA) are applied to combined analysis and scenario development. Operating the plasma with a moderate density peaking factor (n _e0/<n _e> ∼ 1.3) for sufficient fusion gain (Q up to 5) at a low density (f _GW = 0.6–0.8) and the required current drive efficiency produced an internal inductance (l _i(3) ∼ 0.8–0 9) which improves the stability margin for low-n external ideal MHD modes. Based on this first observation, a combined operational space and ideal MHD stability analysis has recently identified Q ∼ 5 ITER SS target plasmas (Polevoi etal 2020 Nucl. Fusion 60 096024), and then the CORSICA scenario modelling suite has been applied to study access to the target plasmas as well as to develop a candidate operation scenario. Ideal MHD stability analysis on the SS plasmas has been performed using DCON embedded in the CORSICA scenario modelling suite. The use of off-axis electron cyclotron current drive (ECCD) with a power level of 20–30MW from the equatorial and upper launchers was essential for the tailoring of the current profile to maintain ideal MHD stability of SS plasmas in ITER. Upgrading the NBI power from the baseline 33MW to 49.5MW provided the necessary current drive capability to allow fully non-inductive Q ∼ 5 operation with an energy confinement enhancement requirement (H ₉₈ ≲ 1.6) similar to that achieved in some experiments in present tokamaks (Petty etal 2020 62nd Annual Meeting of the APS Division of Plasma Physics, Virtual Meeting (USA, 9–13 November 2020); Snyder etal 2019 Nucl. Fusion 59 086017; Solomon etal 2013 Nucl. Fusion 53 093033). The CORSICA simulations of the access to the Q ∼ 5 ITER SS target plasmas show that, provided that the enhancement of the energy confinement (H ₉₈ ∼ 1.5–1.6) is achieved, it is possible for ITER to demonstrate the Q ∼ 5 SSO with NB and EC heating and current drive within the limits of the ITER Central Solenoid (CS)/Poloidal Field (PF) coil systems.

通过利用中性束 (NB) 和电子回旋加速器 (EC) 加热和电流驱动能力，包括它们可预见的升级，可以在 ITER 中潜在地实现稳态 (SS) 等离子体场景，并已评估和开发在Q〜5 ITER SS操作（SSO）方案已经通过结合所有必要的物理和工程部件进行。一套建模代码包括0.5D/1.5D传输和源建模套件（METIS、ASTRA和CORSICA）和理想的MHD稳定性分析代码（KINX和MISHKA）应用于组合分析和场景开发。以中等密度峰值因子 ( n _e0 /< n _e > ∼ 1.3)操作等离子体以获得足够的聚变增益 (Q高达 5) 在低密度 ( f _GW = 0.6-0.8) 和所需的电流驱动效率产生一个内部电感 ( l _i (3) ∼ 0.8-0 9) 这提高了低n外部理想的稳定性裕度MHD 模式。基于第一次观察，组合操作空间和理想 MHD 稳定性分析最近确定了Q ∼ 5 ITER SS 目标等离子体（Polevoi et al 2020 Nucl. Fusion 60096024)，然后应用 CORSICA 场景建模套件来研究对目标等离子体的访问以及开发候选操作场景。使用嵌入在 CORSICA 场景建模套件中的 DCON 对 SS 等离子体进行了理想的 MHD 稳定性分析。使用来自赤道和上部发射器的功率为 20-30MW 的离轴电子回旋电流驱动 (ECCD) 对于调整电流分布以保持 ITER 中 SS 等离子体的理想 MHD 稳定性至关重要。将 NBI 功率从基线 33MW 升级到 49.5MW 提供了必要的电流驱动能力，以允许完全无感Q ∼ 5 操作，并具有能量限制增强要求（H ₉₈≲ 1.6) 类似于目前托卡马克的一些实验中实现的结果（Petty et al 2020 62nd Annual Meeting of the APS Division of Plasma Physics, Virtual Meeting (USA, 9-13 November 2020); Snyder et al 2019 Nucl. Fusion 59 086017; Solomon等2013 Nucl. Fusion 53 093033）。CORSICA 模拟进入Q ∼ 5 ITER SS 靶等离子体表明，只要实现能量限制 ( H ₉₈ ∼ 1.5–1.6)的增强，ITER 就可以证明Q ∼ 5 SSO，在 ITER 中央电磁阀 (CS)/极向场 (PF) 线圈系统的限制内，带有 NB 和 EC 加热和电流驱动。