TY - JOUR
T1 - Impact of localized gas injection on ICRF coupling and SOL parameters in JET-ILW H-mode plasmas
AU - JET EFDA Contributors
AU - Lerche, E.
AU - Goniche, M.
AU - Jacquet, P.
AU - Van Eester, D.
AU - Bobkov, V.
AU - Colas, L.
AU - Czarnecka, A.
AU - Brezinsek, S.
AU - Brix, M.
AU - Crombe, K.
AU - Graham, M.
AU - Groth, M.
AU - Monakhov, I.
AU - Mathurin, T.
AU - Matthews, G.
AU - Meneses, L.
AU - Noble, C.
AU - Petrzilka, V.
AU - Rimini, F.
AU - Shaw, A.
N1 - Publisher Copyright:
© 2014 Elsevier B.V.
PY - 2015/7/22
Y1 - 2015/7/22
N2 - Recent JET-ILW [1,2] experiments reiterated the importance of tuning the plasma fuelling in order to optimize ion cyclotron resonance frequency (ICRF) heating in high power H-mode discharges. By fuelling the plasma from gas injection modules (GIMs) located in the mid-plane and on the top of the machine instead of adopting the more standardly used divertor GIMs, a considerable increase of the ICRF antenna coupling resistances was achieved with moderate gas injection rates (<1.5 × 1022 e/s). This effect is explained by an increase of the scrape-off-layer density in front of the antennas when mid-plane and top fuelling is used. By distributing the gas injection to optimize the coupling of all ICRF antenna arrays simultaneously, a substantial increase in the ICRF power capability and reliability was attained. Although similar core/pedestal plasma properties were observed for the different injection cases, the experiments indicate that the RF-induced impurity sources are reduced when switching from divertor to main chamber gas injection.
AB - Recent JET-ILW [1,2] experiments reiterated the importance of tuning the plasma fuelling in order to optimize ion cyclotron resonance frequency (ICRF) heating in high power H-mode discharges. By fuelling the plasma from gas injection modules (GIMs) located in the mid-plane and on the top of the machine instead of adopting the more standardly used divertor GIMs, a considerable increase of the ICRF antenna coupling resistances was achieved with moderate gas injection rates (<1.5 × 1022 e/s). This effect is explained by an increase of the scrape-off-layer density in front of the antennas when mid-plane and top fuelling is used. By distributing the gas injection to optimize the coupling of all ICRF antenna arrays simultaneously, a substantial increase in the ICRF power capability and reliability was attained. Although similar core/pedestal plasma properties were observed for the different injection cases, the experiments indicate that the RF-induced impurity sources are reduced when switching from divertor to main chamber gas injection.
UR - http://www.scopus.com/inward/record.url?scp=84937773513&partnerID=8YFLogxK
U2 - 10.1016/j.jnucmat.2014.10.074
DO - 10.1016/j.jnucmat.2014.10.074
M3 - Article
AN - SCOPUS:84937773513
SN - 0022-3115
VL - 463
SP - 634
EP - 639
JO - Journal of Nuclear Materials
JF - Journal of Nuclear Materials
M1 - 48571
ER -