Speaker
Description
The dynamics of the edge of tokamak plasmas is understood to be sensitive to the electric field profile. Meanwhile modelling the long-wavelength component of the radial electric field is challenging for core physics, but essential to understand the rotation profile.
The moment-kinetics approach to evaluating transport was introduced under the Excalibur project (report TN-11). This aims to evolve a suitably normalised distribution function on the transport timescale consistently with momentum conservation, across the separatrix and in the presence of the strong changes in parameter values typical of detaching plasmas.
We present the work to date on the Kinetics for Transport (KfT) solver, which implements the moment-kinetics approach.
The solver is being developed in Julia, in a finite element framework with a Chebyshev basis, and supports various configurations for physics studies. Benchmarks and physics studies in 1D1V and 1D2V have been completed, while 2D1V simulations with adiabatic electrons demonstrated the presence of an instability relying on finite pitch angle of the magnetic field.
We have focused on developing a numerical approach that can simulate the sheath boundary conditions with kinetic ions and electrons with scalable performance, to enable 2D2V simulations. The implementation of the moment-kinetics structure and approach to electron preconditioning will be discussed.