[P-EM36_28PM1] 大気圏・電離圏

[PEM36-15] ロケット及び地上観測による中規模伝搬性電離圏擾乱の研究

*山本 衛¹、加藤 寬大¹、石坂 圭吾²、横山 竜宏³、岩上 直幹³、高橋 隆男⁴、田中 真⁴、遠藤 研⁵、熊本 篤志⁵、渡部 重十⁶、山本 真行⁷、阿部 琢美⁸、斎藤 享⁹、津川 卓也³、西岡 未知³、Bernhardt Paul¹⁰、Larsen Miguel¹¹ (1.京都大学生存圏研究所、2.富山県立大学、3.情報通信研究機構、4.東海大学情報教育センター、5.東北大学理学研究科、6.北海道大学理学研究科、7.高知工科大学、8.JAXA宇宙科学研究所、9.電子航法研究所、10.NRL、11.クレムソン大学)

キーワード：MSTID, Sounding rocket, Electric field, GPS-TEC, Observation campaign

Medium-scale traveling ionospheric disturbance (MSTID) is an interesting phenomenon in the F-region. The MSTID is frequent in summer nighttime over Japan, showing wave structures with wavelengths of 100-200 km, periodicity of about 1 hour, and propagation toward the southwest. The phenomena are observed by the total electron content (TEC) from GEONET, Japanese dense network of GPS receivers, and 630 nm airglow imagers as horizontal pattern. It was also measured as Spread-F events of ionograms or as field-aligned echoes of the MU radar. MSTID was, in the past, explained by Perkins instability (Perkins, 1973) while its low growth rate was a problem. Recently 3D simulation study by Yokoyama et al (2009) hypothesized a generation mechanism of the MSTID, which stands on electromagnetic E/F-region coupling of the ionosphere. The hypothesis is that the MSTID first grows with polarization electric fields from sporadic-E, then show spatial structures resembling to the Perkins instability. We recently conducted a observation campaign to check this hypothesis. We launched JASA ISAS sounding rockets S-310-42 and S-520-27 at 23:00 JST and 23:57JST on July 20, 2013 while an MSTID event was monitored in real-time by the GPS-TEC from GEONET. We found 1-5mV/m northeastward/eastward electric fields during the flight. Variation of electric fileds were associated with horizontal distribution of plasma density. Wind velocity was measured by the TME and Lithium releases from S-310-42 and S-520-27 rockets, respectively, showing southward wind near the sporadic-E layer heights. These results are consistent to the expected generation mechanism shown above. In the presentation we will discuss electric-field results and its relationship with plasma density variability together with preliminary results from the neutral-wind observations.