Contour map of electric field calculated for different radial positions and ECH power values
Contour map of electric field calculated for different radial positions and ECH power values

The project aims to characterize and interpret the experimental microwave heated (ECH) plasmas produced in the TJ-II Stellarator. To achieve this, an interpretative transport analysis will be performed using density and heating power scans (similar to Refs [1], [2] and [3]) ¨to systematically study the radial electric field according to, at least, two analytical models. This will be done in cooperation to the Nuclear Science Institute (UNAM).

In addition, data from a new ECH power fine- scan performed during the spring of 2008 in the TJ-II will also be analyzed, and a review of electron thermal energy transport will be performed once the absorption of ECH power by the plasma is known, so that TJ-II data may be added to the international database of energy confinement times. Finally, theoretical and semi-empirical transport models will be tested and compared with the dynamic evolution of TJ-II ECH plasmas to improve the models of Ref. [4], and to apply them to the new cases of transition to lithium walls.

References

[1] V.I. Vargas, D. López-Bruna, J. Herranz, F. Castejón and the TJ-II Team. Experimental electron heat diffusion in ECH plasmas of the TJ-II stellarator, Nucl. Fusion, 47, 1367, 2007.

[2] V.I. Vargas, D. López-Bruna, J. Guasp, J. Herranz, T. Estrada, F. Medina, M.A. Ochando, F. Castejón, J.L. Velasco, J.M. Reynolds, A. Salas and the TJ-II Team. Density dependence of particle transport in ECH plasmas of the TJ-II stellarator, Informe Técnico CIEMAT, n° 1162, febrero 2009.

[3] V.I. Vargas, D. López -Bruna, J. García, A. Fernández, A. Cappa, J. Herranz, F. Castejón. ECH power dependence of electron heat diffusion in ECH plasmas of the TJ-II stellarator, 35th EPS Conference on Plasma Physics, Crete, Greece, 9-13 June, European Physical Society, P5.018 (2008).

[4] I. García-Cortés, D. López-Bruna, F.L. Tabarés, T. Estrada, F. Medina and the TJ-II Team. Spontaneous improvement of TJ-II plasmas confinement, Plasma Phys. Control. Fusion, 44, 1639, 2002.