Japan Geoscience Union Meeting 2014

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International Session (Oral)

Symbol P (Space and Planetary Sciences) » P-EM Solar-Terrestrial Sciences, Space Electromagnetism & Space Environment

[P-EM08_2AM1] Space Weather and Space Climate

Fri. May 2, 2014 9:00 AM - 10:45 AM 411 (4F)

Convener:*Ryuho Kataoka(National Institute of Polar Research), Yusuke Ebihara(Research Institute for Sustainable Humanosphere, Kyoto University), Kanya Kusano(Solar-Terrestrial Environment Laboratory, Nagoya University), Toshifumi Shimizu(Institute of Space and Astronautical Science, JAXA), Yoshizumi Miyoshi(Solar-Terrestrial Environement Laboratory, Nagoya University), Ayumi Asai(Unit for Synergetic Studies of Space, Kyoto University), Tatsuhiko Sato(Japan Atomic Energy Agency), Hidekatsu Jin(National Institude of Information and Communications Technology), Kiminori Itoh(Graduate School of Engineering, Yokohama National University), Hiroko Miyahara(College of Art and Design, Musashino Art University), Chair:Toshifumi Shimizu(Institute of Space and Astronautical Science, JAXA)

10:15 AM - 10:30 AM

[PEM08-13] Diagnosis of coronal shock strength using the activation of large amplitude prominence oscillation

*Takuya TAKAHASHI1, Ayumi ASAI2, Kazunari SHIBATA3 (1.Graduate School of Science, Kyoto University, 2.Unit of Synergetic Studies for Space, Kyoto University, 3.Kwasan and Hida Observatories, Kyoto University)

Keywords:solar flare, coronal mass ejection(CME), shock waves, solar prominence, magnetohydrodynamics(MHD)

X5.4 class solar flare occurred on March 7,2012 which was the second largest flare in this solar cycle. The flare was associated with very fast coronal mass ejection(CME) with the velocity of over 2500km/s. Associated with this flare, a wave-like coronal disturbance(known as EUV wave) was observed to propagate along the solar surface. The observed EUV wave propagated with the average speed of about 670km/s towards the north and 'hit' a polar prominence leading to its large amplitude oscillation. The activated prominence strongly brightened when EUV wave 'pushed' it.Because of the difficulty in direct observation of physical quantities in the corona, the physical nature of the EUV waves is still under discussion. Two main interpretations of EUV waves are the 'fast mode MHD wave/shock' interpretation, and 'non-wave' interpretations.In the images taken with Inner coronagraph(COR1) of the Sun Earth Connection Corona and Heliospheric Investigation(SECCHI) on board Solar Terrestrial Relations Observatory(STEREO)-Behind, we could see a coronal disturbance detached from expanding CME plasma. The time evolution of the disturbance seen in COR1 images was consistent with that of observed EUV wave. Also, Type II radio burst which is thought to be evidence of coronal shock wave was observed simultaneously. Because of that observational evidence, we regard the observed EUV wave as MHD fast mode shock front. Assuming the shock nature of the observed EUV wave, we could also explain prominence acceleration and brightening consistently.Using the initial velocity of activated prominence, we could estimate the coronal shock strength of the EUV wave with the help of linear wave theory. We also check the applicability of linear theory to the shock problem with one dimensional numerical model and ascertained that it is applicable when the shock strength is not strong. Estimated fast mode mach number of the EUV wave was between 1.20 and 1.42, and we could say that the EUV wave was a weak shock front in the corona.