| The confinement performance of plasma is one of the key problems that restrict the miniaturization and economy of the magnetic confinement fusion device.Because there are many complex nonlinear coupled and unstable transport processes in plasma,it is difficult to describe the transport process with a unified physical model.Energy confinement time,the key parameter of the fusion triple product,can directly evaluate the global confinement performance of plasma,so it is widely studied.By studying the relationship between the energy confinement time and various engineering and physical parameters,the energy confinement time scaling provides a simple and direct method to reflect the dependence between the energy transport of plasma and other parameters.The energy confinement time scaling IPB98（y,2）,which is commonly used in internet,is the result of analysis based on ITPA H-mode database.The fully superconducting tokamak EAST has the characteristics of low momentum injection and metal wall in the future fusion reactor device,which is mainly radio frequency wave electron heating.So far,a large amount of H-mode data has been accumulated in EAST.Unlike the ITPA H-mode database,which focuses on neutral beam injection and ion heating,the H-mode data of EAST can just form an effective supplement.In this paper,the H-mode database is constructed in EAST,and the energy confinement time scalings under different heating conditions are formed by linear regression and other research methods.Combined with dimensional analysis,the scale experiments of dimensionless normalized parameters are carried out to verify the reliability of energy confinement time scaling of normalized parameters.First,referring to the international ITPA H-mode database selection criterions,the H-mode database of EAST,including RF wave heating and the cooperation of RF wave and neutral beam,is constructed by combining with the characteristics of steady-state long pulse discharge.In view of the discrepancy of operation regions of some engineering parameters between different auxiliary heating,the whole database is subdivided into NBI-LHW dataset and ECRH-LHW dataset.By the correlation study,principal component analysis and multiple regression analysis of engineering parameters of different datasets,the energy confinement time scalingsτE,EAST,H,NBI-LHW and τE,EAST,H,ECRH-LHW with engineering parameters of different heating conditions in EAST are formed.Compared with the original IPB98（y,2）scaling,the reliability of the prediction results has been improved.The root mean square error（RMSE）has been reduced from 12.9%to 5.5%（NBI-LHW）and from 23.8%to 11.2%（ECRH-LHW）,respectively,both of which have been reduced by more than half.Theoretical and experimental results show that similar dimensionless normalized parameters can describe the same physical laws.In order to form a more general scaling and reveal the physical laws of plasma energy confinement and transport,this paper adds dimensionless normalized parameters to the database analysis and obtains the energy confinement time scaling in the form of dimensionless parameters.The results show that the plasma energy confinement time under different heating conditions shows different degrees of dependence on the normalized parameters.Under the assumption of gyro-Bohm transport,the scaling results of normalized collisionality and normalized beta under different heating conditions show a similar dependence.The energy confinement time increases with the reduction of normalized collisionality,and increases with the increase of normalized beta,showing the reduction of heat transport at low collisionality and the heat transport dominated by electromagnetic turbulence,There is a certain degree of unity in the description of the database.It is significantly different from the independent collisionality dependence and strong negative beta dependence in the international multi-device scaling IPB98（y,2）.In order to verify the reliability of the above normalized parameter scaling results,the relevant normalized parameter scale experiments had been carried out in EAST.The normalized collisionality scale experiments reveal the relationship from both the analysis of global confinement and local transport.The results show that the normalized energy confinement time increases with the reduction of the normalized collisionality,and the collisionality dependence of the thermal transport coefficient at different radial positions is different and is also related to the particle channel.The result is basically consistent with the scaling results of other devices in the world,showing the samiliar moderate collisionality dependence,and also verifies the reliability of the saling results obtained in the EAST database.The normalized beta scale experiments show that the normalized energy confinement time increases with the increase of the normalized beta,which is stronger than the results obtained in the database analysis,showing significant turbulence transport characteristics of electromagnetic properties.The result is significantly different from the other international research results,which show the transport characteristics dominated by electrostatic turbulence. |
