Tritium transport in edge localized mode sELMd high confinement sH-moded plasmas is analyzed
here as a function of density for discharges from the recent trace tritium experimental campaign
performed on Joint European Torus. In this campaign small amounts of tritium have been puffed or
injected swith neutral beam injectorsd into deuterium plasmas fK.-D. Zastrow, J. M. Adams, Yu.
Baranov et al., Plasma Phys. Controlled Fusion 46, B255 s2004dg. Information about the tritium has
been obtained from the evolution of the profiles of neutron emission simulated via the TRANSP fR.
J. Goldston, D. C. McCune, H. H. Towner, S. L. Davis, R. J. Hawryluk, and G. L. Schmidt, J.
Comput. Phys. 43, 61 s1981dg and SANCO sL. Lauro-Taroni, B. Alper, R. Giannella, K. Lawson, F.
Marcus, M. Mattioli, P. Smeulders, and M. Von Hellermann, Proceedings of the 21st European
Conference on Controlled Fusion and Plasma Physics, Montpelier, France, 1994d codes. A strong
inverse correlation of tritium transport with plasma density is found in this analysis. The low tritium
transport at high density is close to neoclassical values while the transport becomes strongly
anomalous in low density plasmas. The thermal transport does not exhibit such a strong density
dependence, leading to a varying ratio of thermal to tritium transport in these discharges. An
interpretation of the density effects on the trace tritium transport, partially based on the test particle
simulations in plasmas with stochastic magnetic field, is proposed. A simple model for the tritium
diffusion coefficient and convective velocity, which includes the modification of the neoclassical
particle diffusion in presence of electromagnetic turbulence fA. I. Smolyakov and P. N. Yushmanov, Nucl. Fusion 35, 383 s1993dg completed with an empirical density dependence, is developed. This
model has positive b dependence in agreement with the results of the similarity experiments
performed for trace tritium transport.
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