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 c urrent is studied by using a magnetospheric model having the dipole magneti c field, the ionosphere with Pedersen conductivity, and a free outer bounda ry. This study is the first step toward realistic modeling of Pi2 pulsation generated by the current wedge model. Numerical calculation reveals that t he ionosphere controls not only damping of the field-line resonance oscilla tion 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 sug gests that the waveform in the middle- and low-latitudes is different from that in high-latitudes.