Lower hybrid current drive in experiments for transport barriers at high {beta}{sub N} of JET (Joint European Torus)

Journal Article · Fri Sep 28 00:00:00 EDT 2007 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.2800490· OSTI ID:21032771

Cesario, R C; Castaldo, C; De Angelis, R; Smeulders, P; Calabro, G; Pericoli, V; Ravera, G ^[1]; Fonseca, A ^[2]; Parail, V; Beurskens, M; Brix, M; Vries, P de; Mailloux, J ^[3]; Zagorski, R ^[4]

---

1. Associazione EURATOM/ENEA sulla Fusione Frascati (Italy)
2. Associacao EURATOM/IST Centro de Fusao Nuclear, 1049-001 Lisbon (Portugal)
3. EURATOM/UKAEA Fusion Association, Culha Science Centre, Abingdon, OX14 3DB (United Kingdom)
4. Institute of Plasma Physics and Laser Microfusion, EURATOM Association Warsaw (Poland)

LHCD has been used in JET experiments aimed at producing internal transport barriers (ITBs) in highly triangular plasmas ({delta}{approx_equal}0.4) at high {beta}{sub N} (up to 3) for steady-state application. The LHCD is a potentially valuable tool for (i) modifying the target q-profile, which can help avoid deleterious MHD modes and favour the formation of ITBs, and (ii) contributing to the non-inductive current drive required to prolong such plasma regimes. The q-profile evolution has been simulated during the current ramp-up phase for such a discharge (B{sub 0} = 2.3 T, I{sub P} = 1.5 MA) where 2 MW of LHCD has been coupled. The JETTO code was used taking measured plasma profiles, and the LHCD profile modeled by the LHstar code. The results are in agreement with MSE measurements and indicate the importance of the elevated electron temperature due to LHCD, as well as the driven current. During main heating with 18 MW of NBI and 3 MW of ICRH the bootstrap current density at the edge also becomes large, consistently with the observed reduction of the local turbulence and of the MHD activity. JETTO modelling suggests that the bootstrap current can reduce the magnetic shear (sh) at large radius, potentially affecting the MHD stability and turbulence behaviour in this region. Keywords: lower hybrid current drive (LHCD), bootstrap current, q (safety factor) and shear (sh) profile evolutions.

• OSTI ID: 21032771
• Journal Information: AIP Conference Proceedings, Vol. 933, Issue 1; Conference: 17. topical conference on radio frequency power in plasmas, Clearwater, FL (United States), 7-9 May 2007; Other Information: DOI: 10.1063/1.2800490; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA). JET EFDA Collaborators; ISSN 0094-243X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
BOOTSTRAP CURRENT
CHARGED-PARTICLE TRANSPORT
COMPUTERIZED SIMULATION
ELECTRON TEMPERATURE
ICR HEATING
JET TOKAMAK
LOWER HYBRID CURRENT DRIVE
MAGNETOHYDRODYNAMICS
PLASMA
PLASMA DENSITY
PLASMA JETS
PLASMA RADIAL PROFILES
PLASMA SIMULATION
SHEAR
STEADY-STATE CONDITIONS
THERMAL BARRIERS
TURBULENCE