関係者各位 太陽と太陽圏に関する下記の特別セミナーを名古屋大学ＳＴＥ研にて実施します。 多くの皆さんのご参加をお待ちしています。 Please join us for a Special Seminar on Sun and Heliosphere in STEL, Nagoya University. 草野完也/K. Kusano (STEL, Nagoya Univ.) --- ******太陽・太陽圏に関する特別セミナー****** **Special Seminar on Sun and Heliosphere** Date: Friday, December 3, 2010, 15:00~17:00 Room: 407, STEL, Nagoya University （名古屋大学共同教育研究施設1号館407号室） Schedule & Abstract: 15:00~16:00 Brian T. Welsch*, George H. Fisher, Yan Li, and Pete W. Schuck (Space Sciences Lab, UC-Berkeley, and Space Weather Lab, NASA-GSFC) *JSPS Fellow Title: Beyond Black & White: How Photospheric Magnetograms Can Teach Us About Solar Activity Abstract: Essentially all solar activity --- variations in the Sun's energetic output in the form of radiation, particles, and fields --- can be traced to the evolution of solar magnetic fields. Beyond the significant ramifications solar activity has for our society, its many facets are of great scientific interest. The magnetic fields that drive solar activity are generated within the Sun's interior, and can extend through the photosphere into the corona, coupling the Sun's interior with its outer atmosphere. Hence, measurements of magnetic fields at the photosphere can provide insights into magnetic evolution both in the interior and the outer atmosphere. While maps of the photospheric magnetic field --- magnetograms --- have been produced routinely for decades, the cadence and quality of such measurements has improved dramatically in recent years, providing new insights into many aspects of the Sun's rich magnetic variability. Here, I will present recent work using magnetograms to understand relationships between active region magnetic evolution and flares and CMEs. 16:00~17:00 Neel Savani (JSPS Fellow, STEL Nagoya University) Title: Evolution of Coronal Mass Ejection Morphology with Increasing Heliocentric Distance Abstract: Interplanetary coronal mass ejections (ICMEs) may travel much faster than the ambient solar wind; in these circumstances if the relative speed between the two exceeds the fast magnetosonic velocity, then a shock wave will form. For a case study event observed in situ, Russell and Mulligan [2002] analysed the sheath region between the shock front and the obstacle to the flow presented by the CME. These results were compared to Earth’s magnetosphere. By measuring the sheath distance they were able to infer a height of an ICME in a direction that is perpendicular to the solar wind flow. We present a similar analysis for 45 events varying between 0.5AU to 5.5AU; thus greatly expanding on previous studies. We find the average ratio of the inferred height to measured radial width, otherwise called the aspect ratio, of an ICME is 2.6 ±1.4. We also compare the results to geometrical predictions that forecast an aspect ratio between 3 and 6. We find that instead of the results following the predictions, they appear to be bounded by the theoretical maximum. This work suggests that CMEs may be distorted during their propagation and thereby becoming more circular; but many assumptions have been included and further work should verify the results by using MHD simulations. -- Kanya Kusano / 草野 完也 Solar-Terrestrial Environment Laboratory, Nagoya University ------------------------------ 名古屋大学 太陽地球環境研究所 総合解析部門 ------------------------------ 独立行政法人海洋研究開発機構（兼務） 地球内部ダイナミクス領域 ------------------------------