Effects Of The Magnetic Topology Changes Induced By Lower Hybrid Waves On The Edge Plasma Transport In Tokamaks

External resonant magnetic perturbations have been found to be beneficial for controlling edge magnetohydrodynamic instabilities and plasma-wall interactions in many current tokamaks.Recent experiments from the Experimental Advanced Superconducting Tokamak(EAST)show that lower hybrid waves(LHWs)can profoundly change the magnetic topology by inducing helical current filaments flowing along magnetic field lines in the scrape-off layer.Such LHW-induced magnetic perturbations have already shown their powerful abilities for controlling edge-localized modes(ELMs)and improving divertor flux distributions in past experiments.On this background,this thesis systematically studies the effect of magnetic topology changes caused by LHWs on the edge plasma transport in tokamaks.Here,it is investigated for the first time how LHW-induced magnetic perturbations affect the edge plasma transport utilizing a self-consistent fluid 3D edge plasma Monte Carlo code EMC3 coupled to the 3D kinetic neutral particle transport code EIRENE,both in double-null and single-null configurations.Good qualitative agreements between simulations and experimental data from various edge diagnostics demonstrate that the EMC3-EIRENE code now is capable of taking into account the LHW-induced magnetic perturbations with both physical and geometrical effects being considered.For the simulated results,the 3D magnetic topology structure is reflected in the plasma properties,due to much stronger parallel field transport compared with cross field diffusion.Combined with experimental observations,the simulation results strongly support that the total current amplitude of LHW-induced filaments increases with an increase in LHW input power.It can further deepen the penetration depth of the additional transport channel by extending the stochastic edge layer,and influence the ratio of heat(or particle)flux between split striated and original strike line on divertor targets.The 3D simulation results also indicate that the additional plasma transport channel induced by LHWs can significantly cause the redistribution of heat load between inner and outer divertor targets,which could not be found by the field line tracing method in previous works.In addition,the redistribution of the divertor flux caused by the synergy of the supersonic molecular beam injection(SMBI)and LHW-induced magnetic perturbations,has been observed on EAST.To reveal the physical mechanism behind,the simulations with good qualitative agreements to the experimental findings are performed for the first time by utilizing EMC3-EIRENE code.The ions and electrons originating from the ionization of injected neutral particles in the plasma edge flow along the magnetic flux tube towards to the divertor,thus directly increasing the divertor flux on the split strike lines in the footprint Combining this with the multi-lobe structure of the edge magnetic topology,actively controlling the divertor flux can be realized by adjusting the SMBI position or the phase of the magnetic perturbations.