Development of Synergetic Fueling Control Compatible with Confinement Improvement and Sustainability of High-Temperature Plasma

高温等离子体控制方案的建立是未来聚变堆的前提。本研究关注了燃料补给的外部控制与等离子体的约束和可持续性的内在特性之间的协同作用。基于积累的物理知识和先进的加注技术，在大型螺旋装置（LHD）上进行了加注方案的实验研究。LHD是一个很好的实验平台，它可以通过外部线圈产生稳态磁场来约束高温等离子体。外部加油对内部变量（温度、密度、压力等）的影响是由于粒子源的产生。热量和粒子传输相互关联，其中直接电荷交换损失、由于再循环引起的间接电荷交换损失、辐射损失和动量损失是非线性耦合的。而弹丸注入堆芯燃料具有较好的效率和安全性， ...更多信息 结果表明，在高密度区，由于核燃料的再循环粒子数明显减少，约束和燃料加注效率下降，以及核芯温度的大扰动引起关注。研究了弹丸喷射和气体吞吐的协同工作，定量分析了二者的协同效应。研究表明，等离子体边界的局部神经压力增加与堆芯约束性能之间的关系。粒子扩散被抑制，即使具有非常大的密度梯度时，通过弹丸注入燃料的条件相结合，使低中性压力在等离子体边界。结合壁调节以提高泵送能力和磁配置以避免中性粒子堵塞是一个关键因素。在这种操作中，密度分布变得非常高，因此中心密度达到每立方米1.2 × 10的21次方，这比聚变反应堆的常规要求大几倍。这一发现提出了一种具有超高密度和相对低温的聚变反应堆的创新方案。应该注意的是，高密度操作减轻了工程需求。这种新的操作制度的文件已经取得了进展，这表明，中心密度和温度都可以保持恒定的重复弹丸燃料与粒子扩散屏障内的渗透。少

Establishment of a control scheme of high-temperature plasmas is prerequisite for a future fusion reactor. This research has paid attention to a synergetic effect of external control of refueling and intrinsic property of confinement and sustainability in plasmas. Based on the accumulated knowledge of physics and developed technology on fueling, experimental studies to develop a fueling scheme have been conducted in the Large Helical Device (LHD). LHD is a good experimental platform since it can generate steady-state magnetic field to confine high temperature plasmas only by external coils. Effect of external fueling on internal variables (temperature, density, pressure, etc.) is attributed to generation of particle source. Heat and particle transports are linked with each other, where direct charge exchange loss, indirect charge exchange loss due to recycling, radiation loss and momentum loss are non-linearly coupled. While core fueling by pellet injection has good efficiency and cons … More equently reduces recycling particles significantly, degradation of confinement and fueling efficiency in the high density regime and large perturbation in the core temperature are concerned. In this research, cooperative operation of pellet injection and gas puff has been explored carefully and their synergetic effect has been quantified. This study indicates the relation between local increase of neural pressure in the plasma boundary and performance of core confinement. Particle diffusion is suppressed even with extremely large density gradient when fueling by pellet injection is combined with the condition to enable low neutral pressure at the plasma boundary. Combination of wall conditioning to enhance pumping capability and magnetic configuration to avoid plugging of neutrals is a key element. In this operation, density profile becomes highly peaked and consequently the central density reached 1.2 times 10 to the 21st per cubic meters which is several times larger than a regular requirement for a fusion reactor. This finding suggests an innovative scenario of a fusion reactor with super-high density and relative low temperature. It should be noted that high density operation mitigates, engineering demand. Documentation of this new operational regime has progressed, which suggests that both central density and temperature can be kept constant with repetitive pellet fueling with penetration inside the particle diffusion barrier. Less