Effects of the Radiative Relaxation and
of the Temperature Dependence of Resistivity
upon the Solar Photospheric Magnetic Reconnection

A. Takeuchi (Yonago Kosen)

     It is widely believed that the solar photospheric magnetic
reconnection occurs at the temperature minimum region.
However, the temperature is increased by the Joule heating
due to the reconnection. As a result the reconnection rate
at the temperature minimum decreases,
because the resistivity decreases with increasing temperature.
On the other hand, the decrease of reconnection rate does not occur
at the photosphere(tau5000=1), because the radiative relaxation
prevents the increase of temperature at the photosphere.
>From the reason, the photosphere might be more favorable place
as the reconnection point.
Thus we investigate the temporal evolution of the photospheric
magnetic reconnection, taking into account the radiative
relaxation and the temperature dependence of resistivity,
performing 2D MHD numerical simulations.
In our calculations we adopt a simple resistivity model
in which the resistivity is proportional to $T^{-3/2}$.
Moreover, the radiative relaxation is taken into account
assuming the Newton's law of cooling.
It is shown that, although the reconnection occurs at
the temperature minimum region in the initial stage,
the reconnection point migrates from the temperature minimum
to the photosphere.