Modelling of Multi-Component Plasma for TOKES

The transport models in multi-component tokamak plasma with various impurity ions are discussed here for implementation in the tokamak integrated code TOKES [1-4]. Impurity transport in the core and boundary plasma of a tokamak is a crucial issue for a fusion reactor device like ITER and DEMO. In steady state reactor operation the tokamak bulk plasma can be contaminated by intrinsic impurities, which can considerably affect the confinement time and bring about the burning plasma dilution. The impurities are originated due to erosion of plasma-facing components and, particularly, during the transient processes like repetitive ELMs, small disruptions etc. Mitigation of ELMs can relax the power loading on PSCs and the problem of core plasma contamination. However, it is still remains unclear to which extend these ELMs must be reduced in order to have a moderate erosion of divertor plates due to physical sputtering during the long-pulse reactor operation to avoid intol

erable accumulation of impurities in the core. Impurities, originated at the plate can migrate through the SOL and penetrate through pedestal region into balk plasma. Effect of impurity screening due to ELMs repulsive force (entraining effect) can protect balk plasma from impurities.

The transport features in tokamak plasma in the presence of arbitrary concentration of various impurity species in different charge state are investigated. Impurity behaviour in the balk and boundary plasma can be simulated in the frame of the integrated code TOKEs. Recently the code was considerably updated [5]. The neoclassical and anomalous transport coefficients where implemented in balk plasma and the pedestal region together with ELM model. The SOL and divertor region were elaborated. These improvements and the impurity transport models, described here will enable a self-consistent simulation of impurity dynamic in muli-component complex plasma, where impurity ions dominate and determine the transport properties.

The various transport models for multi-component plasma have been reviewed and proper equations, describing a multi-component plasma transport have been suggested for implementation in the integrated code TOKES.

Umfang: V, 137 S.