Incorporating molecular and impurity effects into kinetic parallel electron transport modelling of scrape-off layer detachment

This project focuses on detailed modelling of the interplay of kinetic, parallel electron transport along magnetic fields lines with atomic & molecular physics occurring near the divertor. The goal is to understand how detachment is affected by non-local effects (collisionless electrons streaming from the core-edge to the divertor), especially its response to transient loading during instability driven outbursts from the core (i.e. ELMs). The project will build upon the SOL-KiT code, developed by Stefan Mijin (Imperial PhD Scholarship student, in year 3) under the supervision of Dr Kingham (Imperial) & Dr Militello (CCFE). Currently, SOL-KiT implicitly solves the Vlasov-Fokker-Planck equation for electrons and fluid equations for a single ion species along a field-line. It includes a collisional-radiative model for neutral atoms.

In order to properly consider detachment, extra physical effects are required; molecular physics (i.e. accounting for D2+) and impurity ion species. SOL-KiT will be upgraded to include these. Kinetic modelling will be used for ions and potentially neutrals too. The PhD student will use this enhanced code to investigate how kinetic effects influence the process of detachment, the parameter space for steady state detachment and its sensitivity and response to ELMs. Synthetic spectra will be obtained, to inform analysis and design of experiments.