Nonlinear Analysis of Radial Evolution of Solar Wind in the Inner Heliosphere

Abstract

We analyzed the radial evolution of solar wind in the inner heliosphere using nonlinear time series tools such as correlation dimension $D_{2}$ , correlation entropy $K_{2}$ and multifractal analysis, to get information regarding the inherent nonlinearity associated with the solar wind data and to know how it is affected by the radial distance from the Sun. Our study provides some detailed information regarding the change of dynamics of the fast solar wind with radial distance in the inner heliosphere, apart from confirming the previous observation about the chaotic nature in the dynamics of the slow solar wind. Also we found that the fast wind in the inner heliosphere is dominated by stochastic fluctuations. As the wind is flowing radially away from the Sun, stochastic fluctuation in the fast wind decreases. The stochastic fluctuation present in the data is a clear indication of the Alfvenic fluctuation associated with the solar wind. Finally, our analysis suggests that Alfvenic fluctuation strongly influences the solar wind as it flows radially outwards to mask the nonlinear component associated with the fast wind.