Takuma Matsumoto, Takeru Ken Suzuki
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.
View original:
http://arxiv.org/abs/1109.6707
No comments:
Post a Comment