Energy transfer of trapped electron turbulence in tokamak fusion plasmas

The first principle gyrokinetic simulations[1,2,3] of trapped electron turbulence in tokamak fusion plasmas demonstrate the energy transfers from the most linearly unstable modes at high to intermediate via parametric decay process in a short period of linear-nonlinear transition phase. Dominant nonlinear wave-wave interactions occur near the mode rational surface . In fully nonlinear turbulence, inverse energy cascade occurs between a cutoff wave number and with a power law scaling , while modes with are suppressed. The numerical findings show fair agreement with both the weak turbulence theory[4,5] and realistic experiments on Tore Supra tokamak[6].



References

[1] L. Qi, “Energy transfer of trapped electron turbulence in tokamak fusion plasmas” Sci. Rep. 12, 5042 (2022)

[2] J. M. Kwon, et al., “ITG–TEM turbulence simulation with bounce-averaged kinetic electrons in tokamak geometry” Comput. Phys. Commun. 215 81–90 (2017)

[3] L. Qi et al., “Bounce-averaged gyrokinetic simulation of trapped electron turbulence in elongated tokamak plasmas” Nucl. Fusion 57 124002 (2017)

[4] F. Y. Gang, P. H. Diamond and M. N. Rosenbluth, “A kinetic theory of trapped-electron-driven drift wave turbulence in a sheared magnetic field.” Phys. Fluids B: Plasma Phys. 3, 68 (1991)

[5] T. S. Hahm and W. M. Tang, “Weak turbulence theory of collisionless trapped electron driven drift instability in tokamaks” Phys. Fluids B: Plasma Phys. 3, 989 (1991)

[6] P. Hennequin et al., “Scaling laws of density fluctuations at high-k on Tore Supra” Plasma Phys. Control. Fusion 46, B121–B133 (2004).