Authors: Kelvin Lule1, Laxman Adhikari2, Gary Zank2, Ashok Silwal2

Based on Zank et al. (2012), we analyzed the trend of nonlinear timescale (τnl) and Alfven timescale (τA) by using 1 AU observation of solar wind parameters and turbulence quantities. The nonlinear timescale (τnl) represents the perpendicular eddy turnover time, and the Alfven timescale (τA) represents the typical propagation time of the Alfven wave along the eddy of size L||. We have presented these time scales as a function of time in solar maxima and solar minima of solar cycles 23 and 24. For weak turbulence, we found τA << τnl, and in some cases where τA >> τnl, it is regarded as strong turbulence. Additionally, If τA ~ τnl turbulence is considered as in a “critically balanced” state. In a “critically balanced” state of turbulence, the forces driving the turbulence are balanced by the forces dissipating the energy of the turbulence. This balance occurs on scales where the Coriolis force and the nonlinear advection term of the turbulence equation are of comparable magnitude. In this state, the energy cascades from large scales to small scales, where it is eventually dissipated as heat.