Alfvén Characteristic Behavior In Tokamak

Discrete Alfvén eigenmodes(i.e.,?TAEs,with ? being a measure of plasma pressure gradient),within the magnetohydrodynamic(MHD)description,are quasi-marginally stable modes,which can be readily destabilized by energetic particles in burning plasmas.These kinetically unstable modes could potentially affect steady-state operations of tokamaks.In this paper,we describe the kinds of devices for controlled nuclear fusion,and the physical characteristic of shear Alfvén wave and?TAE,then,discuss the simulation program of ?TAEs.What's more,the stability features of ?TAEs are delineated upon the(s,?)equilibrium model.Their multiple branches are demonstrated with MHD computations as well as MHD-gyrokinetic hybrid simulations.The kinetic excitations are presented for the ?TAEs via wave-particle resonances.These ?TAEs instabilities are also discussed for varied tokamaks.Here,we focus on the relationship between ?TAEs and bootstrap current with a MHD simulation code and a gyrokinetic-MHD hybrid simulation code in two typical scenarios in ITER,and compare these typical scenarios with two ordinary scenarios about physical characteristics of ?TAEs.These ?TAEs are always lying in the region of high bootstrap current.However,they are not corresponding absolutely in pure radio frequency scenario(one of typical scenarios)because of large-?.Moreover,we illustrate the multiple branches of ?TAEs in those typical scenarios,and find high-order modes trapped by the lower potential well.?TAEs exist widely in ITER scenarios with bootstrap current However,?TAEs are quasi-marginally stable in MHD description and could be readily destabilized by energetic particles in hybrid simulation via wave-particle resonances.