Dynamic Investigation Of Li-plasma Interaction Next To The Li-Coating Divertor Plate Using Particle-in-Cell Technique

Plasma facing materials(PFMs)can significantly affect the performance of magnetically confined core plasma.Impact of particle and energy flux incident on PFM divertor target could produce impurities,which can be propagated to the core plasma and affect the plasma performance.Additionally,transportation of excessive amount of particle and energy flux from core plasma to the divertor target can limit the lifetime and reliability of the divertor material.Hence,it is great challenge to find a suitable material which can withstand incident particle and energy fluxes for continuous operation,at the same time,emitting less impurity particles.Lithium(Li)coated materials and liquid Lithium materials manifest adequate performance when used as first wall or divertor plasma facing components(PFCs),such as control of edge localized modes(ELMs),increased confinement and low sputtering yield.Lithium coating on the divertor target reduces the particle and energy recycling from the surface of PFCs which occurs due to incident plasma ions and deuterium atoms on the wall.This reduced particle recycling results in substantial reduction in temperature gradient in the core plasma and increment in energy confinement time.Hence,a rigorous quantitative and qualitative analysis of Li-plasma interactions and edge plasma dynamics is the essential part of the plasma fusion research.In the present work,1D3 V Particle-In-Cell(PIC)simulations have been performed to study the effects of Li divertor target material on the edge plasma utilizing Monte Carlo Collisions(MCC)package to define various interactions among charged and neutral particles.Source of plasma is deuterium plasma which is defined between two Li divertor target plates and the whole simulation domain characterizes the scrape off layer(SOL).Li impurities are generated from the Li target as a result of sputtering or evaporation due to impact of deuterium ions on it.Particle recycling and secondary electron emission(SEE)from the divertor plate have also been considered.Transportation of plasma particles and neutral particles has been investigated which directly affects the divertor plasma characteristics.Li divertor shows a significant reduction in plasma temperature and incident heat and particle flux on the target as plasma particles lose their energy in various collisions with the Li impurity and through radiation losses.