Effects Of Energetic Ions On The Pressure Of EAST Plasma

The plasma equilibrium is an very important basis to the tokamak plasma.Com-pared with the magnetic equilibirum,the kinetic equilibrium has more detailed infor-mation such as the plasma pressure,plasma current and safety factor profiles.And the kinetic equilibiurm has the pedestal structure for H-mode plasma which the mag-netic equilibrium missed.So how to yield a kinetic equilibrium which is reliable and self-consistent is an important work.And,with the power of auxiliary system such as Neutral Beam injection(NBI)and Ion Cyclotron Resonance Heating(ICRH)on EAST is increasing,the effects of fast ions produced by NBI and ICRH are more and more important.However,the effects of fast ions didn’t taken into account when make an equilibrium on EAST before,especially we know few about the features of the ICRH-induced fast ions.So studying how fast ions affect the equilibrium becomes an urgent topic.We obtain the reliable and consistent kinetic profiles,fitted by the new fitting tool-EASTfit,using the magnetic diagnostics data and kinetic diagnostics data of a typ-ical EAST H-mode discharge,including Neutral Beam injection and Ion Cyclotron Resonance Heating.Using TRANSP/NUBEAM/TORIC code,with the obtained mag-netic diagnostics data kinetic profiles,the NBI and ICRH induced fast ion pressures are yielded,updating the total pressure profile,meanwhile,the total current profile is updated by constraining the bootstrap current.Finaly,the kinetic equilibria at two time-slices with different auxiliary heatings are reconstructed by using the updated total pressure profile and total current profile via EFIT code,and we obtain two equilibria.It is found that the fast-ion pressure might be up to one-third of the plasma pressure and the contribution is mainly in the core region of plasma due to the nuetral beam injection power is primarily deposited in the core region.The fast-ion current contributes mainly in the core region while contributes little to the pedestal current.A steep pressure gra-dient in the pedestal region and the bootstrap current due to the pressure gradient in the pedestal region are observed.Comparing the two equilibria,it is found that NBI dominates the heating.To analyze the effect of ICRF-induced fast ions on the plasma pressure of EAST,the simulations are performed by using former yielded kinetic equilibrium and TRANSP/TORIC codes.It is found that the ICRF induced fast-ion pressure cannot be negligble when the ICRH power is sufficiently high.The magnitude of the total ion pressure can be raised up to 60%of the total pressure as the input power is above 3 MW.It is shown that the pressure profile is also significantly modified and broadened when the resonant layer moves from high field side or low filed side.When the antenna position is changed by moving from the middle plain to the up side,the pressure profile is also broadened.These results might provide an option for profile control on EAST.