Kiel 2011 – scientific programme

Parts | Days | Selection | Search | Updates | Downloads | Help

P: Fachverband Plasmaphysik

P 15: Theorie/Modellierung I

P 15.4: Talk

Wednesday, March 30, 2011, 15:10–15:25, HS C

Modification of local plasma parameters by impurity injection — •Mikhail Koltunov and Mikhail Z. Tokar — Institute of Energy and Climate Research -- Plasma Physics, Forschungszentrum Jülich GmbH, Association EURATOM-FZJ, Partner in the Trilateral Euregio Cluster, Jülich, Germany

Injection of impurities into the plasma of fusion devices may significantly change the global plasma behavior, e.g., through the radiation from the plasma core and modification of transport properties. However, even at puffing rates significantly lower than those being of importance for global plasma characteristics, noticeable changes can happen locally, close to the injection position. This in turn affects the impurity penetration process itself.

In this contribution we propose a model describing plasma behavior in the vicinity of strong sources of impurities. The model is based on a fluid description of electrons, main and impurity ions and takes into account the plasma quasi-neutrality, Coulomb collisions of background and impurity charged particles, radiation losses and sinks of particles to bounding material surfaces. Particle, momentum and energy balances are deduced by integrating transport equations within the clouds of neutral and singly charged impurities, both inside and beyond the scrape-off layer of the puffing limiter.

Computations are done for the conditions of impurity seeding experiments in the tokamak TEXTOR. The model allows to simulate two-dimensional images of radiation losses which can be directly compared with experimental observations.