Speaker
Description
See full abstract here http://ocs.ciemat.es/EPS2019ABS/pdf/P5.1057.pdf
This work presents details of the Wendelstein W7-X stellarator Neutral-Beam-Injector (NBI) system, and its effect on the beam dump, duct, heat efficiency and plasma current. During the last stellarator W7-X operation phase, the first of two NBI injectors (NI21) was taken into operation. It was equipped with two hydrogen sources with a neutral power before the duct of 2×1.7MW and a maximum pulse-length of 6.5s. A second NBI system (NI20) is in preparation for the next experimental campaign and each injector can be equipped with a total of four sources each. NI21 was commissioned first as it was calculated that the current drive is opposite to the bootstrap current in the standard magnetic field configuration [2]. NI20 will be symmetrically oriented to NI21 and drives current in the direction of the bootstrap current. One source of NI21 was installed at a location optimized for maximum port transmission and another source at a location for maximum heating efficiency [1]. The predictions for the heat load on the port liner and the beam dump are compared with the experimental findings for operating NI21 into the empty torus and into W7-X plasmas. In addition, the effects of NI operation on the overall plasma current are assessed.
References
[1] N. Rust et al., Fusion Eng. And Design 86 (2011)
[2] Schmidt et al., 31st EPS Conference on Plasma Phys. London, 2004, Vol. 28G, P-1.200
