Japan Geoscience Union Meeting 2018

Presentation information

[JJ] Oral

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

[P-EM19] Heliosphere and Interplanetary Space

Thu. May 24, 2018 3:30 PM - 5:00 PM 304 (3F International Conference Hall, Makuhari Messe)

convener:Ken Tsubouchi(Tokyo Institute of Technology), Masaki N Nishino(Institute for Space-Earth Environmental Research, Nagoya University), Yasuhiro Nariyuki(富山大学人間発達科学部), Chairperson:Nariyuki Yasuhiro

4:15 PM - 4:30 PM

[PEM19-10] 3-years optical observations of neutral helium distribution in interplanetary space by Hisaki

*Atsushi Yamazaki1, Go Murakami1, Kazuo Yoshioka2, Tomoki Kimura3, Fuminori Tsuchiya4, Masato Kagitani4, Takeshi Sakanoi4, Naoki Terada5, Yasumasa Kasaba5, Ichiro Yoshikawa6 (1.Institute of Space and Astronautical Science / Japan Aerospace Exploration Agency, 2.Graduate School of frontier Science, The University of Tokyo, 3.Nishina-Center for Accelerator Based Science, RIKEN, 4.Planetary Plasma and Atmospheric Research Center, Graduate School of Science, Tohoku University, 5.Graduate School of Science, Tohoku University, 6.The University of Tokyo)

Keywords:EUV spectral observation, Interstellar wind and gas, Interplanetary neutral helium, HISAKI stellite

The Hisaki (SPRINT-A) satellite has a main scientific topic of the planetary magnetspheic physics and atmospheric evoluiton by long-term observations, but carried out the non-planetary observation at the time when there is no oppotunity for observation of all planets. One of those observations is an observation of helium atom resonance scattering from interplanetary space. A material in the interstellar medium (ISM) travels into the heliosphere over the heliopause due to the relative velocity between the heliosphere and interstellar gases. The helium atoms move into about 0.5Au of the neighboring from the sun without ionizing because of its high ionization energy. The helium atoms are bent by sun gravity along the Keplerian orbit and forms a high density region on the down wind side, which is called helium cone. The distribution of helium atoms in the helium cone can estimate the speed and direction of the interstellar wind, and the density and the temperature of the helium atom in interstellar gases. The interplanetary observation is one of powerful tools to recognize the interstellar medium from inside the heliosphere. This study was carried out from the 1970s, but the recent IBEX satellite observation results show that the distribution of interstellar gasses change dinamically. The Hisaki satellite carried out the observaiont of the resonance scattering from inside the helium cone during November and December. In this presentation, the Hisaki's observation results of the helium cone three times in years of 2015 - 2017 are shown, and the change of the wind direction are reported.