Overview of transport, fast particle and heating and current drive physics using tritium in JET plasmas
Stork, D. and Baranov, Y. and Belo, P. and Bertalot, L. and Borba, D. and Brzozowski, J.H. and Challis, C.D. and Ciric, D. and Neu, R and O'Mullane, M and Contributors, JET EFDA (2005) Overview of transport, fast particle and heating and current drive physics using tritium in JET plasmas. Nuclear Fusion, 45 (10). S181S194. ISSN 00295515 (https://doi.org/10.1088/00295515/45/10/S15)
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Results are presented from the JET Trace Tritium Experimental (TTE) campaign using minority tritium (T) plasmas (n(T)/n(D) <3. Thermal tritium particle transport coefficients (DT, nu(T)) are found to exceed neoclassical values in all regimes, except in ELMy Hmodes at high densities and in the region of internal transport barriers (ITBs) in reversed shear plasmas. In ELMy Hmode dimensionless parameter scans, at q(95) 2.8 and triangularity delta = 0.2, the T particle transport scales in a gyroBohm manner in the inner plasma (r/a <0.4), whilst the outer plasma particle transport scaling is more Bohmlike. Dimensionless parameter scans show contrasting behaviour for the trace particle confinement (increases with collisionality, nu* and beta) and bulk energy confinement (decreases with nu* and is independent of beta). In an extended ELMy Hmode data set, with rho*, nu*, and q varied but with neoclassical tearing modes (NTMs) either absent or limited to weak, benign core modes (4/3 or above), the multiparameter fit to the normalized diffusion coefficient in the outer plasma (0.65 <r/a <0.8) gives DT/Bphi similar to rho*(2.46) nu*(0.23) beta(1.01) q(2.03). In hybrid scenarios (q(min) similar to 1, low positive shear, no sawteeth), the T particle confinement is found to scale with increasing triangularity and plasma current. Comparing regimes (ELMy Hmode, ITB plasma and hybrid scenarios) in the outer plasma region, a correlation of high values of DT with high values Of nu(T) is seen. The normalized diffusion coefficients for the hybrid and ITB scenarios do not fit the scaling derived for ELMy Hmodes. The normalized tritium diffusion scales with normalized poloidal Larmor radius (rho(theta)* = q rho*) in a manner close to gyroBohm (similar to rho(sigma)*(3)), with an added inverse P dependence. The effects of ELMs, sawteeth and NTMs on the T particle transport are described. Fastion confinement in currenthole (CH) plasmas was tested in TTE by tritium neutral beam injection into JET CH plasmas. gammarays from the reactions of fusion alpha and beryllium impurities (Be9(alpha, n gamma)C12) characterized the fast fusionalpha population evolution. The gammadecay times are consistent with classical alpha plus parent fast triton slowing down times (tau(Ts) + tau(alpha s)) for high plasma currents (Ip > 2 MA) and monotonic qprofiles. In CH discharges the gammaray emission decay times are much lower than classical (tau(Ts) + tau(alpha s)), indicating alpha confinement degradation, due to the orbit losses and particle orbit drift predicted by a 3D FokkerPlanck numerical code and modelled using TRANSP.
ORCID iDs
Stork, D., Baranov, Y., Belo, P., Bertalot, L., Borba, D., Brzozowski, J.H., Challis, C.D., Ciric, D., Neu, R, O'Mullane, M ORCID: https://orcid.org/0000000221604546 and Contributors, JET EFDA;

Item type: Article ID code: 31301 Dates: DateEvent1 October 2005PublishedNotes: Symposium on Theory of Magnetic Confinement held at the 20th IAEA Fusion Energy Conference, Vilamoura, PORTUGAL, NOV 0106, 2004 Subjects: Science > Physics Department: Faculty of Science > Physics Depositing user: Pure Administrator Date deposited: 13 Jul 2011 08:56 Last modified: 28 Sep 2024 01:29 URI: https://strathprints.strath.ac.uk/id/eprint/31301