Integrated Tokamak Modelling and Simulation (ITMS)

The general topic of this project is the integrated theoretical-numerical treatment of tokamak-type fusion devices. By this "Integrated Tokamak Modelling and Simulation (ITMS)" we mean some sufficiently self-consistent theoretical-numerical description of the entire tokamak plasma extend-ing from the walls to the centre of the plasma, thus encompassing both the core and the edge (scrape-off layer, or SOL) regions, including divertor and pedestal physics. The main goals of the project are (i) building suitable ITMS tools (i.e., integrated computer codes covering the entire tokamak plasma), and (ii) performing with these tools interpretative and predictive simulations for existing tokamaks (preferably ASDEX Upgrade in Garching and JET in Culham), as well as predictive simulations for projected next-step tokamaks (mainly ITER). The envisaged ITMS tools will be built on the basis of existing fluid codes which are already well est-ablished and in widespread use within the tokamak modelling community. While, at present, SOL codes employ two-dimensional geometry whereas core codes are one-dimensional, our self-con- sistent approach envisages two-dimensional modelling in the entire plasma region. To achieve these goals, we will extend the validity of an existing two-dimensional SOL code (preferably B2- SOLPS) up to the centre of the plasma ("uniform integrated approach"), rather than coupling existing core and SOL codes at a common boundary ("modular integrated approach"). Moreover, in the SOL and/or core regions additional physics, such as neutral and impurity trans-port, will be implemented via existing codes used as subroutines to the main code. Special atten-tion will be devoted to improving the boundary conditions and anomalous-transport coefficients, and on implementing drifts, currents, and radial electric fields. With the ITMS tools thus developed, we will be able to study phenomena which intrinsically require a uniform integrated approach and hence cannot be treated properly with existing tools. These include pellet vs. gas-puffing fuelling, helium pumping, impurity accumulation in the core, and edge-localised modes (ELMs). The results from our new code will be benchmarked with other existing integrated (however modular) codes (COCONUT and CORSICA 2). The present project is intended as the first step of a pertinent long-term effort and will include collaboration with a significant number of experts from several relevant experimental and model-ling groups.

The general topic of this project is the integrated theoretical-numerical treatment of tokamak-type fusion devices. By this "Integrated Tokamak Modelling and Simulation (ITMS)" we mean some sufficiently self-consistent theoretical-numerical description of the entire tokamak plasma extend-ing from the walls to the centre of the plasma, thus encompassing both the core and the edge (scrape-off layer, or SOL) regions, including divertor and pedestal physics. The main goals of the project are (i) building suitable ITMS tools (i.e., integrated computer codes covering the entire tokamak plasma), and (ii) performing with these tools interpretative and predictive simulations for existing tokamaks (preferably ASDEX Upgrade in Garching and JET in Culham), as well as predictive simulations for projected next-step tokamaks (mainly ITER). The envisaged ITMS tools will be built on the basis of existing fluid codes which are already well est-ablished and in widespread use within the tokamak modelling community. While, at present, SOL codes employ two-dimensional geometry whereas core codes are one-dimensional, our self-con- sistent approach envisages two-dimensional modelling in the entire plasma region. To achieve these goals, we will extend the validity of an existing two-dimensional SOL code (preferably B2- SOLPS) up to the centre of the plasma ("uniform integrated approach"), rather than coupling existing core and SOL codes at a common boundary ("modular integrated approach"). Moreover, in the SOL and/or core regions additional physics, such as neutral and impurity trans-port, will be implemented via existing codes used as subroutines to the main code. Special atten-tion will be devoted to improving the boundary conditions and anomalous-transport coefficients, and on implementing drifts, currents, and radial electric fields. With the ITMS tools thus developed, we will be able to study phenomena which intrinsically require a uniform integrated approach and hence cannot be treated properly with existing tools. These include pellet vs. gas-puffing fuelling, helium pumping, impurity accumulation in the core, and edge-localised modes (ELMs). The results from our new code will be benchmarked with other existing integrated (however modular) codes (COCONUT and CORSICA 2). The present project is intended as the first step of a pertinent long-term effort and will include collaboration with a significant number of experts from several relevant experimental and model-ling groups.