Connecting the Sun and the Solar Wind: The First 2.5 Dimensional Self-consistent MHD Simulation under the Alfv\'en Wave Scenario

TL;DR

This study presents the first 2.5D self-consistent MHD simulation from the solar surface to interplanetary space, demonstrating how Alfvén waves contribute to coronal heating and solar wind acceleration through wave reflection, mode conversion, and turbulence.

Contribution

It introduces a novel 2.5D simulation approach that models the entire system from the photosphere to interplanetary space, capturing complex wave interactions and heating mechanisms.

Findings

Alfvén waves undergo reflection and mode conversion in the solar atmosphere.

Shock heating from slow mode waves is key to coronal heating.

Turbulent cascade and shock heating accelerate the solar wind.

Abstract

The solar wind emanates from the hot and tenuous solar corona. Earlier studies using 1.5 dimensional simulations show that Alfv\'{e}n waves generated in the photosphere play an important role in coronal heating through the process of non-linear mode conversion. In order to understand the physics of coronal heating and solar wind acceleration together, it is important to consider the regions from photosphere to interplanetary space as a single system. We performed 2.5 dimensional, self-consistent magnetohydrodynamic simulations, covering from the photosphere to the interplanetary space for the first time. We carefully set up the grid points with spherical coordinate to treat the Alfv\'{e}n waves in the atmosphere with huge density contrast, and successfully simulate the solar wind streaming out from the hot solar corona as a result of the surface convective motion. The footpoint motion excites Alfv\'{e}n waves along an open magnetic flux tube, and these waves traveling upwards in the non-uniform medium undergo wave reflection, nonlinear mode conversion from Alfv\'{e}n mode to slow mode, and turbulent cascade. These processes leads to the dissipation of Alfv\'{e}n waves and acceleration of the solar wind. It is found that the shock heating by the dissipation of the slow mode wave plays a fundamental role in the coronal heating process whereas the turbulent cascade and shock heating drive the solar wind.