The Distributions of Characteristic Parameters During Long-Period Modulation Heating in the Polar Region Ionosphere

In this paper, we present an improved model associated with a three-dimensional heating model with a stratified DC approach model considering inhomogeneity of ionosphere to study the distributions of characteristic parameters of lower ionosphere during long-period modulation heating in the polar region. The distributions of Pederson conductivity, Hall conductivity, and excitation current are discussed in detail. The distributions of Pedersen conductivity reveal that the electron temperature plays more important role in spatial distribution of Pedersen conductivity, and the electron density has a small effect on the distribution of Pedersen conductivity. The distributions of Hall conductivity exhibit that the main contribution of the negative disturbance of Hall conductivity comes from the temperature-dependent electron collision frequency and the positive disturbance comes from electron density. The distributions of excitation current indicate that the amplitude variation of excitation current is dominated by the Pedersen conductivity and Hall conductivity, and the shape variation (the rotation of long axis) of excitation current is dominated by Hall conductivity. Above all, these findings suggest that the difference between steady-state time scale of electron temperature (milliseconds) and that of electron density (minutes) will greatly administrate the distributions of Pedersen conductivity and Hall conductivity. Excitation current, which leads to the generation of ultralow frequency/extremely-low frequency/very low frequency, will be further affected. Finally, the estimated amplitude of the magnetic field in model is consistent with the previous experimental results in the long period modulation heating, which proves the accuracy of the model. The amplitude of magnetic field can reach several hundreds of pT at the modulation period of 50 s. Key Points We present an improved model associated with a three-dimensional heating model with a stratified DC approach model The distributions of Pederson conductivity, Hall conductivity, and excitation current are discussed in detail The difference between steady-state time scale of electron temperature and density will administrate the distributions of conductivities