Numerical Study On Effects Of Drift Kinetic Damping And Plasma Shear Flow On Resistive Wall Modes In CFETR

Tokamak is one of the best magnetic confinement circulators that can obtain fusion energy,and the China Fusion Engineering Test Reactor?CFETR?is independently developed and designed by China on the basis of fully absorbing the relevant technologies of Internation Thermonuclear Experimental Reactor?ITER?.The magnetohydrodynamic instabilities caused by the failure to satisfy the equilibrium conditions will limit the achievable normalized beta values?_N??and the economic benefits of fusion reactors.And the external kink mode?XK?can be completely suppressed by the ideal conductor wall close to the plasma boundary.For the real conductor wall,there is a residual instability mode after the resistance wall restrains the XK,which is called resistive wall mode?RWM?.Although the time scale of the RWM is slow,it will still cause the plasma to break.In this work,we adopt an equilibrium for a 13MA CFETR steady-state scenario,with the major radius beingR₀=7.2m and the on-axis vacuum toroidal field B₀?28?6.53T.At present,there are two control methods for RWM,active control and passive control.In this work,we study the parallel viscous force damping and drift kinetic damping on RWM and find out the parameter range and threshold value which can make RWM stable.The first chapter briefly describes the background of fusion energy.the fusion energy is safety?clean amd sustainability which is the best way to solve the energy problem in the world.If the fusion reaction is going to take place,it needs to satisfy the Lawson criterion.For the magnetic confinement fusion device,the energy confinement time needs to reach the order of seconds.The MHD instability will affect the steady-state operation of the device and lead to the discharge termination.In chapter II,the MARS-K model is introduced,which transforms the scalar pressure in the ideal MHD equations into a pressure tensor to couple the dynamical effects.And the parameters?_D will be mainly studied in the following part.In this chapter,we also focus on the 13MA steady-state CFETR equilibrium used in this work,as well as the three plasma rotation profiles used in the following chapter.In chapter III,the influence of plasma shear flow on stability of RWM is discussed.In this part,we only consider the resonance of the mode and ion parallel sound wave.The effect of the parallel viscous coefficient,pressure parameter and the plasma flow are studied.And the effects of three kind of plasma shear fow on the stability of RWM are also studied.In chapter IV,the influence of drift kinetic damping on stability of RWM is discussed.In this part,we only consider the resonance of the mode and precession drift of the trapped thermal ion.For larger pressure parameter,there are two kinetic model branch.Finally,a brief summary end the thesis.