TY - JOUR
T1 - JET scrape-off-layer ionization at lower hybrid wave launching
AU - Petrzilka, V.
AU - Mailloux, J.
AU - Ongena, J.
AU - Corrigan, G.
AU - Fuchs, V.
AU - Goniche, M.
AU - Parail, V.
AU - Belo, P.
AU - Ekedahl, A.
AU - Jacquet, P.
AU - Mayoral, M. L.
AU - Silva, C.
AU - Stamp, M.
PY - 2012/7
Y1 - 2012/7
N2 - We present in this paper modelling of the JET scrape-off layer (SOL) including direct SOL ionization by launched lower hybrid (LH) waves. For that purpose, the two-dimensional fluid code EDGE2D-NIMBUS was modified in order to account for possible enhanced ionization in the SOL, due to the LH power absorbed by the electrons in a layer extending in the radial direction from the launcher. By taking the direct LH SOL ionization into account, the observed modification of the density in front of the LH antenna during a LH power and gas injection, can be explained. The JET grill private SOL limiters, acting as sinks for the particles, are also included in the model. We compare the efficiency of gas puffing from the top and the outer mid-plane for SOL density enhancement and improvement in LH coupling. The observed reduction of the temporal variation of the LH wave reflection coefficient and of measured saturated currents in the SOL during ELMs, is explained. The density depletion, by ponderomotive forces in front of the grill, is estimated.
AB - We present in this paper modelling of the JET scrape-off layer (SOL) including direct SOL ionization by launched lower hybrid (LH) waves. For that purpose, the two-dimensional fluid code EDGE2D-NIMBUS was modified in order to account for possible enhanced ionization in the SOL, due to the LH power absorbed by the electrons in a layer extending in the radial direction from the launcher. By taking the direct LH SOL ionization into account, the observed modification of the density in front of the LH antenna during a LH power and gas injection, can be explained. The JET grill private SOL limiters, acting as sinks for the particles, are also included in the model. We compare the efficiency of gas puffing from the top and the outer mid-plane for SOL density enhancement and improvement in LH coupling. The observed reduction of the temporal variation of the LH wave reflection coefficient and of measured saturated currents in the SOL during ELMs, is explained. The density depletion, by ponderomotive forces in front of the grill, is estimated.
UR - http://www.scopus.com/inward/record.url?scp=84863312050&partnerID=8YFLogxK
U2 - 10.1088/0741-3335/54/7/074005
DO - 10.1088/0741-3335/54/7/074005
M3 - Article
AN - SCOPUS:84863312050
SN - 0741-3335
VL - 54
JO - Plasma Physics and Controlled Fusion
JF - Plasma Physics and Controlled Fusion
IS - 7
M1 - 074005
ER -