TY - GEN
T1 - Initial boron powder injection experiments in WEST
AU - the WEST Team
AU - Bodner, G.
AU - Diallo, A.
AU - Lunsford, R.
AU - Nagy, A.
AU - Bortolon, A.
AU - Moreau, P.
AU - Gallo, A.
AU - Gunn, J. P.
AU - Guillemaut, C.
AU - Tsitrone, E.
AU - Bourdelle, C.
AU - Vermare, L.
AU - Pellissier, F. P.
AU - Unterberg, E. A.
AU - Klepper, C. C.
N1 - Publisher Copyright:
© 2021 47th EPS Conference on Plasma Physics, EPS 2021. All right reserved.
PY - 2021
Y1 - 2021
N2 - Boron powder (< 150 μm) was injected at various drop rates into lower single null (LSN) L-mode discharges in WEST, using a recently installed impurity powder dropper (IPD) developed at PPPL, with the objective of improving wall conditioning to facilitate H-mode access. These discharges featured Ip~ 0.5 MA, tpulse= 12-30 s, ne,0~ 4 × 1019m-3, and PLHCD~ 4.5 MW. During powder injection, a clear reduction in SOL DI and low-Z intrinsic impurity line intensities was observed, suggesting a reduction in recycling and possible screening of low-Z impurities. Additionally, the WI line intensity was observed to increase at both the outer lower divertor and at the ICRH limiter. In the subsequent discharges, however, the pre-injection WI line intensity decreased, possibly indicating a conditioning effect. These WEST experiments also observed improvements in stored energy (up to 25%) during powder injection. The increases in stored energy may be the result of stabilized ion temperature gradient (ITG) modes due to fuel dilution similar to gaseous impurity seeding experiments.
AB - Boron powder (< 150 μm) was injected at various drop rates into lower single null (LSN) L-mode discharges in WEST, using a recently installed impurity powder dropper (IPD) developed at PPPL, with the objective of improving wall conditioning to facilitate H-mode access. These discharges featured Ip~ 0.5 MA, tpulse= 12-30 s, ne,0~ 4 × 1019m-3, and PLHCD~ 4.5 MW. During powder injection, a clear reduction in SOL DI and low-Z intrinsic impurity line intensities was observed, suggesting a reduction in recycling and possible screening of low-Z impurities. Additionally, the WI line intensity was observed to increase at both the outer lower divertor and at the ICRH limiter. In the subsequent discharges, however, the pre-injection WI line intensity decreased, possibly indicating a conditioning effect. These WEST experiments also observed improvements in stored energy (up to 25%) during powder injection. The increases in stored energy may be the result of stabilized ion temperature gradient (ITG) modes due to fuel dilution similar to gaseous impurity seeding experiments.
UR - http://www.scopus.com/inward/record.url?scp=85119515935&partnerID=8YFLogxK
M3 - Conference contribution
AN - SCOPUS:85119515935
T3 - 47th EPS Conference on Plasma Physics, EPS 2021
SP - 609
EP - 612
BT - 47th EPS Conference on Plasma Physics, EPS 2021
PB - European Physical Society (EPS)
T2 - 47th EPS Conference on Plasma Physics, EPS 2021
Y2 - 21 June 2021 through 25 June 2021
ER -