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Time evolution plots of radial particle flux from oHW (black), MHW (green), MHW w/o ZF (green), and MHW w/o ZD (red) for a ¼ 2.

Time evolution plots of radial particle flux from oHW (black), MHW (green), MHW w/o ZF (green), and MHW w/o ZD (red) for a ¼ 2.

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Article
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The generations of zonal flow (ZF) and density (ZD) and their feedback on the resistive drift wave turbulent transport are investigated within the modified Hasegawa-Wakatani model. With proper normalization, the system is only controlled by an effective adiabatic parameter, α, where the ZF dominates the collisional drift wave (DW) turbulence in the...

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Context 1
... all the cases, we observe that the fluctuations first grow linearly due to the resistive DW instability, where the modifications will not affect the growth of the DW in the linear regime (e.g., see Fig. 1 for a ¼ 2). Note that, in the late linear stage, the simulations of oHW and MHW are dominated by the mode ðk x ; k y Þ ¼ ð0:2; 1Þ, while those of MHW w/o ZF/ZD are governed by ðk x ; k y Þ ¼ ð0:2; 0:6Þ. The growth rates from the simulations are, respectively, 0.025 and 0.057, which agree with the analytic result of resistive DW in the ...
Context 2
... (as an example, the growth rate of ZF can be $0:1 in our normalized unit 22,23 for a ¼ 2, i.e., c zf $ 0:1jx ci ). The ZF and/or ZD will, in turn, affect the DW, and the system will be saturated eventually when the particle flux C n approximately balances the dissipation, D a ¼ a À1 Ð ½^ að~ n À ~ /ފ 2 dx, due to the parallel resistivity. From Fig. 1 we see that, the saturated particles fluxes are quite different, where the time-averaged C n at the saturated state from t ¼ 400 to t ¼ 1000 are 0.36 (oHW), 7:4  10 À3 (MHW), 2:2  10 À2 (MHW w/o ZD), and 0.4 (MHW w/o ZF), respectively. This is consistent with the standard recognition that the ZF can largely suppress the anomalous ...
Context 3
... when the amplitudes of DWs become the order of unity as a result of growth from the linear state, the secondary instabilities will lead to the generation of the ZF and/or ZD, which will, in turn, suppress the DW turbulence and thus reduce the radial particle flux. We find that the ZF itself can significantly reduce the particle flux as shown in Fig. 1, whereas the ZD can reduce the transport only through its synergy with ...

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Citations

... Hasegawa-Mima model does not [5]), ii) finite frequency (so that resonant interactions are possible [6]), and iii) a proper treatment of zonal flows [7]. The model is well known to generate high levels of large scale zonal flows, especially for C 1 [8][9][10]. It has been studied in detail for many problems in fusion plasmas including dissipative drift waves in tokamak edge [11,12], subcritical turbulence [13], trapped ion modes [14], intermittency [15,16], closures [17][18][19], feedback control [20], information geometry [21] and machine learning [22]. ...
... and Ω ± k is given in (10). Note that these coefficients are complex, and have different phases in general. ...
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