[Zurück]

M. Willensdorfer, E. Wolfrum, E. Fable, F. Ryter, F. Aumayr, R. Fischer, S. Rathgeber, P. Sauter, P. Schneider, B. Sieglin, . ASDEX Upgrade Team:
"Transport analysis of the density build-up after L-H transition in ASDEX Upgrade";
in: "Proc. 39th EPS Conference on Plasma Physics", EPS, 36F, 2012, ISBN: 2-914771-79-7, S. 1 - 4.

The H-mode is characterized by the formation of an edge transport barrier (ETB) in energy
and particle transport, which results in enhanced energy and particle confinement. A matter of
particular interest is, wether the improvement in particle confinement is caused by a reduction of
diffusive transport and/or by an increase of the inward directed convective transport in the edge,
as proposed in [1, 2]. The efficiency of fueling without pellets, i.e. gas puffing, in ITER is likely
to be insufficient to reach the required operational density [3]. Therefore, an inward directed
convective transport would reduce the necessity of a high particle source inside the last closed
flux surface (LCFS). Transport analysis of transient events, like ELMs, gas modulation and
L-H transition, is the only possibility to separate the contributions of convective and diffusive
transport. For this reason, we used the density build-up following the L-H transition to perform
predictive transport analysis, using the ASTRA code [4], and to asses the respective roles of
diffusion and convection in the density build up.