The scalings of the thermal energy confinement time in EAST H-mode plasmas

Abstract

This paper describes scalings of the H-mode confinement database of neutral beam injection (NBI)-lower hybrid wave (LHW) and electron cyclotron resonant heating-LHW plasmas in the EAST tokamak. Fundamental information of the EAST H-mode database and the details of calculation of the thermal energy confinement time in EAST are presented. The result of the scaling model ${\tau _{{\text{E,EASTS,H,NBI - LHW}}}}$ of the thermal energy confinement time in NBI-LHW plasmas with root-mean-square-error ${\text{RMSE}} = 5.5\% $ , compared with the multi-machine scaling model ${\tau _{{\text{th,98}}y{\text{2}}}}$ derived from the multi-machine database (mainly NBI heating) with ${\text{RMSE}} = 12.9\% $ , is obtained. The scaling ${\tau _{{\text{E,EAST,H,NBI - LHW}}}}$ presents a similar dependency on plasma current and power loss and a lower dependency on plasma density and elongation, but stronger dependency on toroidal field than in ${\tau _{{\text{th,98}}y{\text{2}}}}$ . The scaling ${\tau _{{\text{E,EAST,H,ECRH - LHW}}}}$ demonstrates a similar dependency on plasma current and power loss and lower dependency on plasma density, but a negative dependency with large error bars on elongation compared with ${\tau _{{\text{E,EAST,H,NBI - LHW}}}}$ in NBI-LHW plasmas. The comparison of EAST models with the more recent multi-tokamak scaling ITPA20-IL shows a similar engineering dependency on plasma current, power loss and plasma density, but opposite dependency on toroidal field.

Keywords

• energy confinement time
• EAST
• H-mode
• NBI-LHW
• ECRH-LHW