Recent developments in theory-based modelling of core heavy impurity transport are presented, and shown to be ecessary for quantitative description of present experiments in JET and ASDEX Upgrade. The treatment of heavy impurities is complicated by their large mass and charge, which result in a strong response to plasma rotation or any small background electrostatic field in the plasma, such as that generated by anisotropic external heating. These forces lead to strong poloidal asymmetries of impurity density, which have recently been added to numerical tools describing both neoclassical and turbulent transport. Modelling predictions of the steady-state two-dimensional tungsten impurity distribution are compared with experimental densities interpreted from soft X-ray diagnostics. The modelling identifies neoclassical transport enhanced by poloidal asymmetries as the dominant mechanism responsible for tungsten accumulation in the central core of the plasma. Depending on the bulk plasma profiles, neoclassical temperature screening can prevent accumulation, and can be enhanced by externally heated species, demonstrated here in ICRH plasmas.
|Publication status||Published - 2014|
|Event||41st EPS Conference on Plasma Physics, EPS 2014 - Berlin, Germany|
Duration: 1 Jan 2014 → …
|Conference||41st EPS Conference on Plasma Physics, EPS 2014|
|Period||1/1/14 → …|
All Science Journal Classification (ASJC) codes
- Atomic and Molecular Physics, and Optics
Casson, F. J., Angioni, C., Belli, E. A., Bilato, R., Mantica, P., Odstrcil, T., ... Reinke, M. L. (2014). Theoretical description of heavy impurity transport and its application to the modelling of tungsten in JET and ASDEX upgrade. Paper presented at 41st EPS Conference on Plasma Physics, EPS 2014, Berlin, Germany.