Optimization of the N∥ Upshift in the DIII-D high field side lower hybrid current drive experiment

IF 2.1 2区物理与天体物理 Q2 PHYSICS, FLUIDS & PLASMAS

Plasma Physics and Controlled Fusion Pub Date : 2024-05-09 DOI:10.1088/1361-6587/ad44d6

Grant Rutherford, Samuel J Frank, Andrew H Seltzman, Paul T Bonoli, Stephen J Wukitch

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引用次数: 0

Abstract

High field side lower hybrid current drive (LHCD) is one potential candidate for efficient non-inductive current drive in tokamak power plants, and the first test of this technology will occur on the DIII-D tokamak during the 2024 campaign. Previous LFS launch experiments operated in the multi-pass regime and relied on scrape-off layer interactions to close the spectral gap. In the DIII-D experiment, single-pass damping is achievable via an upshift in the parallel refractive index

N∥

caused by mode converting twice (slow

→

fast

→

slow). This mode conversion affects the ray trajectories and can lead to enhanced

N∥

upshift depending on where mode conversion occurs. Compared to multi-pass absorption experiments, the optimization of launched

N∥

and plasma parameters can be counter-intuitive: increased density may increase efficiency and smaller

N∥,launch

tend to damp closer to the separatrix. A hard x-ray camera installed to measure the bremsstrahlung (50–250 keV) radiation from LHCD-generated fast electrons is capable of verifying the trends reporting in this paper through comparison to the ray-tracing/Fokker–Planck codes GENRAY/CQL3D.

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优化 DIII-D 高场侧下部混合电流驱动实验中的 N∥ Upshift

高场侧低混合电流驱动（LHCD）是托卡马克发电厂高效无感电流驱动的潜在候选技术之一，该技术的首次测试将于2024年在DIII-D托卡马克上进行。以前的 LFS 发射实验是在多通道机制下运行的，依靠刮除层的相互作用来关闭光谱间隙。在DIII-D实验中，通过模式转换两次（慢→快→慢）引起的平行折射率N∥上移，可以实现单通阻尼。这种模式转换会影响射线轨迹，并根据模式转换发生的位置导致增强的 N∥ 上移。与多通道吸收实验相比，发射 N∥ 和等离子体参数的优化可能与直觉相反：密度增加可能会提高效率，而较小的 N∥、发射倾向于阻尼更接近分离矩阵。为测量 LHCD 产生的快速电子的轫致辐射（50-250 keV）而安装的硬 X 射线照相机能够通过与射线跟踪/福克-普朗克代码 GENRAY/CQL3D 的比较来验证本文所报告的趋势。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Plasma Physics and Controlled Fusion 物理-物理：核物理

CiteScore

4.50

自引率

13.60%

发文量

224

审稿时长

4.5 months

期刊介绍： Plasma Physics and Controlled Fusion covers all aspects of the physics of hot, highly ionised plasmas. This includes results of current experimental and theoretical research on all aspects of the physics of high-temperature plasmas and of controlled nuclear fusion, including the basic phenomena in highly-ionised gases in the laboratory, in the ionosphere and in space, in magnetic-confinement and inertial-confinement fusion as well as related diagnostic methods. Papers with a technological emphasis, for example in such topics as plasma control, fusion technology and diagnostics, are welcomed when the plasma physics is an integral part of the paper or when the technology is unique to plasma applications or new to the field of plasma physics. Papers on dusty plasma physics are welcome when there is a clear relevance to fusion.