Propagation property of transient MHD impulses in the Magnetosphere‐Ionosphere System: The 2D model of the Pi2 pulsation

Propagation property of the 2D‐coupled MHD wave induced from an impulsive current is studied by using a magnetospheric model having the dipole magnetic field, the ionosphere with Pedersen conductivity, and a free outer boundary. This study is the first step toward realistic modeling of Pi2 pulsation generated by the current wedge model. Numerical calculation reveals that the ionosphere controls not only damping of the field‐line resonance oscillation but also its frequency. The field‐line resonance oscillation exhibits the fundamental mode structure along the field line in the plasmasphere. In high latitudes, there are waves bouncing between the ionospheres. This suggests that the waveform in the middle‐ and low‐latitudes is different from that in high‐latitudes.