Lower hybrid current drive in experiments for transport barriers at high βn of JET (Joint European Torus)

R.C. Cesario, C. Castaldo, A. Fonseca, R. De Angelis, V. Parail, P. Smeulders, M. Beurskens, M. Brix, G. Calabrò, P. De Vries, J. Mailloux, V. Pericoli, G. Ravera, R. Zagorski

Research output: Contribution to conferencePaper

1 Citation (Scopus)

Abstract

LHCD has been used in JET experiments aimed at producing internal transport barriers (ITBs) in highly triangular plasmas (δ≈0.4) at high βN (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 (B0=2.3T, IP=1.5MA) 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. © 2007 American Institute of Physics.
Original languageEnglish
DOIs
Publication statusPublished - 2007
Externally publishedYes
Event17th Topical Conference on Radio Frequency Power in Plasmas - , United States
Duration: 1 Jan 2007 → …

Conference

Conference17th Topical Conference on Radio Frequency Power in Plasmas
CountryUnited States
Period1/1/07 → …

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All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)

Cite this

Cesario, R. C., Castaldo, C., Fonseca, A., De Angelis, R., Parail, V., Smeulders, P., ... Zagorski, R. (2007). Lower hybrid current drive in experiments for transport barriers at high βn of JET (Joint European Torus). Paper presented at 17th Topical Conference on Radio Frequency Power in Plasmas, United States. https://doi.org/10.1063/1.2800490