[P-EM12] Coupling Processes in the Atmosphere-Ionosphere System

[PEM12-31] Deformation of the Solar Quiet Current Vortex Driven by Non-Migrating Tides Over Asia

★Invited Papers

*Yang-Yi Sun¹、PengYu Zhang¹、Chieh-Hung Chen²、Aisa Yisimayili³、ZhiQiang Mao¹ (1.China University of Geosciences、2.Chengdu University of Technology、3.Earthquake Agency of Xinjiang Uygur Autonomous Region)

キーワード：Solar Quiet Current, Non-Migrating Tides

The Solar quiet (Sq) current system in the ionosphere at ~110 km altitude, primarily driven by atmospheric tides, exhibits significant longitudinal variations that have not been fully explored. This study provides a detailed analysis of the Sq current morphology over Asia (from 130° to 70°E) based on ground-based geomagnetic field observations. The results reveal that the Sq current vortex deforms into a tilted ellipse as it moves northwestward over East Asia, eventually disintegrating over Central Asia, particularly during the northern Hemisphere winter. To understand the underlying mechanism, we estimated the current generated by the polarized electric field (J_Ep) in the E region, using non-migrating tidal winds from the TIMED/TIDI (the TIMED Doppler Interferometer on board the Thermosphere Ionosphere Mesosphere Energetics Dynamics satellite) wind observation in the mesosphere and lower thermosphere region. The estimation, based on the fundamental polarization concept, suggests that J_Ep contributes to the observed displacement and deformation of the Sq current. Additionally, the Observing Procedure Experiment was employed to reconstruct the Sq current, confirming its deviation from the geomagnetic equator. The findings demonstrate that nonuniform winds modulate the ionospheric current system, leading to an inhomogeneous E-region dynamo. This study provides the first in-depth analysis of Sq current evolution in this longitudinal sector, highlighting the role of wind-electricity-magnetism interactions in shaping the complex behavior of the Sq current over Asia.