|
内容記述 |
The effect of fusion-born alpha particles on the helical core (HC), a long-lived ideal saturation state of the m/n= 1/1 kink/quasi-interchange mode, is studied in the ITER-like hybrid scenario. Using a magnetohydrodynamic-PIC simulation, we find that within the ITER operating alpha pressure (βα ∼1%), alpha particles weakly suppress the linear growth rate of the kink/quasi-interchange mode. However, the radial displacement of the HC magnetic axis during the quasi-steady state (δHC) tends to increase with βα. As βα increases further, the m/n= 1/1 fishbone or energetic particle mode becomes unstable, and δHC continues to increase until it reaches an upper limit where the HC state becomes too unstable. In addition to the m/n = 1 mode (HC), the broad spectrum of the shorter wavelength resistive pressure-driven MHD modes can be destabilized after HC formation when either the plasma resistivity or the width of the low magnetic region exceeds a threshold. Due to their multi-helicity, their spatial overlapping leads to the stochatization of the magnetic field, facilitating the radial mixing of alpha particles and bulk plasmas. |
