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

[PEM12-P07] 共鳴散乱ライダーによるCa/Ca^＋同時・同領域観測

*江尻 省^1,2、桂川 眞幸^3,1、橋本 彩香³、小林 蒼汰³、三好 咲也子³、宮城 晃³、津田 卓雄³、中村 卓司^1,2 (1.国立極地研究所、2.総合研究大学院大学、3.電気通信大学)

キーワード：共鳴散乱ライダー観測、カルシウム原子とイオン、中間圏・下部熱圏、中性・イオン結合

To measure temporal variation in vertical density distributions of meteoric metal atom and ion, as a dynamical tracer in the Mesosphere and Thermosphere, and investigate the vertical mass transport, we are developing a resonance scattering lidar for simultaneous observation of Calcium atom (Ca) and ion (Ca⁺). The lidar system has an injection-locked Ti:Sapphire laser with a broad frequency tunability as a transmitter and receives the resonance scatter signals by a telescope with ~80 cm diameter. The laser oscillator is designed so that the oscillation frequencies can be tuned simultaneously to the resonance lines of Ca and Ca⁺ ion. Laser pulses of two wavelengths were emitted from a single laser resonator simultaneously, and common-volume and simultaneous measurements of Ca and Ca⁺ densities were successes in Tachikawa (36N, 139E) at 10:50-21:10 UT on December 24, 2024. Both of Ca and Ca⁺ layers were observed at 80 – 105 km during all the night. Dense-thin layers of Ca+ were seen at ~100 km before 13 UT and ~95 km around 17 UT which were slightly higher altitudes than top of Ca layer. After 16:45 UT until sunrise, Ca⁺ layer had a dense-thin layer with a few km FWHM at 90 – 95 km, while Ca did not show such a dense-thin layer. In this presentation, we will discuss dynamics and chemical process of neutral atom and ion coupling by comparison in density, height and fine structures between Ca and Ca⁺.