A model of the thermal expansion of the solar corona with allowance for radiation

The Parker model is modified to describe a rapid temperature increase from the region of temperature minimum to the coronal base and to relate the electron density in the region of the temperature minimum (similar to 0.85 x 10(11) cm(-3) according to the modified model) to that at the orbit of the Earth (similar to 7.42 cm(-3) according to the model). The coronal temperature reaches its maximum (1.8 x 10(6) K) at the Parker critical point; physical processes at this point are left beyond the scope of the model. It is suggested to consider the expanding solar corona as a self-heating system in which heating of the solar corona is related to the transonic regime of its expansion, which is maintained by the high coronal temperature.