Solar wind and its evolution

Takeru K Suzuki

doi:10.5047/eps.2011.04.012

Abstract

By using our previous results of magnetohydrodynamical simulations for the solar wind from open flux tubes, I discuss how the solar wind in the past is different from the current solar wind. The simulations are performed in fixed one-dimensional super-radially open magnetic flux tubes by inputing various types of fluctuations from the photosphere, which automatically determines solar wind properties in a forward manner. The three important parameters which determine physical properties of the solar wind are surface fluctuation, magnetic field strengths, and the configuration of magnetic flux tubes. Adjusting these parameters to the sun at earlier times in a qualitative sense, I infer that the quasi-steady-state component of the solar wind in the past was denser and slightly slower if the effect of the magneto-centrifugal force is not significant. I also discuss effects of magneto-centrifugal force and roles of coronal mass ejections.

Highlights

Young solar-type stars are generally very active: X-ray flux is up to ∼1000 times larger than the present-day sun (Gudel et al, 1997; Gudel, 2004), and the X-ray temperature is higher (Ribas et al, 2005; Telleschi et al, 2005)
Solar wind is hot plasma emanating from the Sun, and the mass loss rate amounts to ∼1012 g s−1 (2 × 10−14 M yr−1) at present
Summary Based on our previous results of MHD simulations, I discuss the evolution of the quasi-steady-state component of solar wind from open flux tubes

Summary

Introduction

Young solar-type stars are generally very active: X-ray flux is up to ∼1000 times larger than the present-day sun (Gudel et al, 1997; Gudel, 2004), and the X-ray temperature is higher (Ribas et al, 2005; Telleschi et al, 2005). The simulations are performed in fixed one-dimensional super-radially open magnetic flux tubes by inputing various types of fluctuations from the photosphere, which automatically determines solar wind properties in a forward manner. The three important parameters which determine physical properties of the solar wind are surface fluctuation, magnetic field strengths, and the configuration of magnetic flux tubes.

Results

Conclusion