Based on OMFIT framework and HL-2M parameters, this paper comprehensively considers the changes in plasma density, temperature, and other transport quantities caused by the interaction of neutral beam injection(NBI) and electron cyclotron wave(ECW) with plasma. The changes in the Shafranov shift of the plasma magnetic surface center are also evaluated. Theoretically, the influence of NBI on the deposition location and current drive efficiency of the ECW is studied. According to the findings, NBI affected the position location and efficiency of the electron cyclotron current drive (ECCD) deposited on both high field side (HFS) and low field side (LFS). NBI can relocate the ECW power deposition location to the core and increase the current drive efficiency when the ECW power is deposited on the LFS. When the NBI power increases to 7 MW, the ECCD deposition location can shift to the core by roughly 0.15 normalized small radii, and the current drive efficiency can be improved by 1.3 times. Moreover, as NBI power increases, the radial region where the dimensionless current drive efficiency equals to zero gets closer to the plasma edge. When ECW power is deposited on the HFS paraxial, increasing NBI power causes the ECW deposition location to move toward the plasma edge, thus lowering current drive efficiency. This trend is caused by an increase in NBI power, which can increase the Shafranov shift of the plasma center, increase the electron density, and change the electron temperature. These studies hold great significance for achieving more effective current drive and controlling the plasma current profile and neoclassical tearing mode instability.
On the basis of the OMFIT integrated simulation platform and the parameters of the HL-2M device, a hybrid scenario with a typical safety factor q profile is simulated using the joint injection method of neutral beam and electron cyclotron wave with a normalized toroidal beta (βN) of 2.39. At the same time, by analyzing the effect of impurity concentration (Zeff) and pedestal density (ne,ped) on confinement, a higher parameters hybrid scenario is obtained, with βN reaching 3.118. The research results indicate that the turbulent stabilization effect caused by Zeff gradually decreases from strong to weak with the increase of Zeff, whereas the radiation power loss increases linearly as Zeff increases. Consequently, there exists an optimal Zeff value for optimal confinement. In addition, it is found that the optimal Zeff value decreases with the increase of ne,ped. The research results are crucial for the HL-2M device to accomplish the 1 MA advanced scenario discharge target, and they serve as a reference for future impurity seeding experiments.
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