Modeling and measurement of energetic particle slowing down in Wendelstein 7-X

Nuclear Fushion

article

Samuel A. Lazerson¹  David Pfefferlé²  Michael Drevlak¹  Håkan Smith¹  Joachim Geiger¹  Simppa Äkäslompolo³  Pavlos Xanthopoulos¹  Andreas Dinklage¹  Oliver Ford¹  Paul McNeely¹  Norbert Rust¹  Sergey Bozhenkov¹  Dirk Hartmann¹  Kian Rahbarnia¹  Tamara Andreeva¹  Jonathan Schilling¹  Christian Brandt¹  Ulrich Neuner¹  Henning Thomsen¹  Robert C. Wolf¹ 

[1]Max-Planck-Institut für Plasmaphysik

[2]University of Western Australia

[3]Aalto University

关键词: stellarator;    simulation;    validation;    energetic particles;    NBI;    heating;    current drive;   

DOI  :  10.1088/1741-4326/ac0771

来源: Institute of Physics Publishing Ltd.

【 摘 要 】

The energetic particle slowing down model in the BEAMS3D stellarator neutral beam code is compared to analytic models and experimental data from the Wendelstein 7-X experiment (W7-X). Recently, the first neutral beam experiments were performed in W7-X, providing validation of neutral beam deposition codes (Lazerson S.A.et al2020Nucl. Fusion60076020). This work builds upon that work, and follows the gyro-center orbits of the neutral-beam-generated fast ions to the plasma boundary. Slowing down times based on measurements of diamagnetic energy changes are compared to simulation data. A discharge solely heated by neutral beam injection is used to compare neoclassical heat flux estimates to neutral beam fueling, heating, and current drive. Experimental estimates of electron heat diffusivity suggest that electron turbulence is destabilized by density peaking in the discharge. Neutral beam current drive dominates over bootstrap current, resulting in a reversal of the toroidal current, as seen experimentally. Particle losses and heat flux through the equilibrium boundary are described. The effects of the magnetic configuration and plasma density on such parameters are also assessed. Benchmarking based on analytic estimates and other energetic particle codes is presented.

【 授权许可】

Unknown