Turbulence exerts significant influence over radial transport in the edge region of tokamak plasmas, a critical factor in magnetic confinement for fusion experiments. Despite its substantial

impact, our understanding of turbulence in this context remains limited. Coherent structures are fundamental in the realm of turbulent transport within fusion plasmas. Entropy and complexity, derived from information theory, serves as a valuable tool to quantify the level of order or disorder in turbulent plasmas. Notably, these coherent structures contribute to the observation of low spectral entropy values in data obtained from space plasmas and numerical simulations of magnetohydrodynamic turbulence.

In this analysis, we concentrate on two-dimensional numerical simulations of the modified Hasegawa-Wakatani equations, which provide a simplified nonlinear model for electrostatic resistive drift-wave turbulence in plasmas. We construct a bifurcation diagram illustrating the transition from a turbulent regime to one dominated by zonal flows, effectively suppressing turbulence. To gauge the level of spatial order or disorder during this transition, we compute the Jensen-Shannon complexity-entropy index of the velocity, derived from the electrostatic potential. This index uses the normalized power of shearlet coefficients as a probability distribution.

Our findings reveal that the turbulent regime exhibits a higher degree of entropy and a lower degree of complexity, contrasting with the regime dominated by zonal flows characterized by lower entropy values and a higher degree of complexity. These results hold the potential to advance our understanding of nonlinear processes within drift-wave turbulence in fusion plasmas.

Keywords: Plasma, information theory, nonlinear dynamics, turbulence.