The nature of reflection and mode conversion of MHD waves in the inductiveionosphere: Multistep mode conversion between divergent and rotational electric fields

The nature of reflection and mode conversion of MHD waves at the high-latit udinal inductive ionosphere is analyzed, based on the current conservation law of wave modes. The term "inductive ionosphere" refers to the nonzero ro tational electric field or nonzero compressional magnetic field in the refl ection process of shear Alfven waves on the ionosphere. The finite rotation al electric field causes mutual induction between the divergent and rotatio nal current systems at the ionosphere. The one-step Hall effect for the div ergent electric field of the shear Alfven wave produces a rotational Hall c urrent and excites the ionospheric surface compressional wave. The Hall eff ect for the rotational electric field of an ionospheric surface compression al wave produces a divergent Hall current (two-step Hall effect), which fee ds back the compressional magnetic energy to the reflected field-aligned cu rrent. We find that the renormalization of the ionospheric rotational elect ric field to the reflection process of the shear Alfven wave causes some pe culiarities in the distribution of ionospheric currents and mode-converted wave magnetic fields. Such peculiarities become particularly obvious in the high conducting ionosphere. For example, in the ionospheric current distri butions, a considerable component of the ionospheric divergent current is a ccounted for by the divergent Hall current. The rotational Hall and Pederse n currents cancel each other out and lead to zero total ionospheric rotatio nal current. The amplitude of the poloidal magnetic field transmitted from the toroidal magnetic field of the incident shear Alfven wave shows a nonli near dependence on Sigma(H)/Sigma(P). It also shows a new type of effective ionospheric shielding effect in the Sigma(P)/Sigma(A) parameter space for a fixed Sigma(H)/Sigma(P) condition. We assert that the inductive response of the ionosphere should become an indispensable concept for reflection, mo de conversion, transmission, and generation of various phenomena relating t o the field-aligned current system.