Eigenvalue analysis of feedback instability in a magnetosphere–ionosphere (M–I) coupling model has been extended to study the stabilization mechanism of high-frequency shear Alfvén modes by introducing both an inhomogeneous conductivity… Click to show full abstract
Eigenvalue analysis of feedback instability in a magnetosphere–ionosphere (M–I) coupling model has been extended to study the stabilization mechanism of high-frequency shear Alfvén modes by introducing both an inhomogeneous conductivity profile and an ionospheric Alfvén resonator. Stabilization of high-frequency modes is attributed to change of the effective impedance due to the non-uniform ionospheric conductivity along the field line rather than the collision-induced flow shear, while low-frequency modes relevant to auroral arc excitation remain unstable. An effective impedance model incorporating the inhomogeneous conductivity profile is also developed as an extension of the height-integrated ionosphere model.
Journal Title: Physics of Plasmas
Year Published: 2023
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