Tokamak code TOKES. Models and implementation

During a few past years the code TOKES was developed aiming at an integrated simulation of plasma equilibrium states and surface processes in tokamaks. The code calculates multi-fluid plasma processes in the core plasma and the scrape-off layer (SOL), and atomic processes at the vessel surface and in the vessel volume, by a sequence of time steps for the whole discharge. The dynamics of the magnetic field and the currents in the plasma and the poloidal field coils are accounted for. The models include fuelling by spreading cold atoms in the confined plasma volume and heating by neutral beams, transport of radiation and neutrons in the whole vessel and the hot plasma in the core, and plasma fluxes through the separatrix or the limiter magnetic surface into SOL towards the wall. Surface response to the load such as sputtering and vaporization are considered, and also the propagation of emitted material atoms in the vessel and their ionization and charge-exchanges in SOL and the confined plasma. At the current stage some components possibly represent only temporary solutions and may in future be further elaborated or even fully replaced with different models. Nevertheless, the code already offers a rather self-consistent approach of tokamak simulation for engineers and scientists with background knowledge of tokamak physics, and also a convenient user interface. Usually one simulation takes a few hours on a conventional personal computer and provides many data for a deep insight into tokamak operation. So far there are several publications that shortly describe the features of TOKES and its capabilities of applications for the future tokamak ITER. However, the present TOKES needs validations against experimental results on existing big tokamaks; only then predictive simulations for ITER and the DEMO concept can gain confidence. This document comprises the intermediate state of the code, including the physical and mathematical background of incorporated models and design details, in order to promote further elaboration and development of this tokamak simulator, and to provide detailed background material for referencing, including material not mentioned in the available publications.