ICRR seminar |
Speaker: Saku Tsuneta Hinode Science Center (HSC) & Advanced Technology Center (ATC) in National Astronomical Observatory of Japan |
Date and time: January 25 (Wed), 15:30- |
Title: 太陽観測衛星「ひので」が明らかにした磁気的宇宙 "Magnetic Universe as revealed with solar observation satellite Hinode" |
Abstract: It is a fascinating fact that a solitary star like the Sun emits intense X-rays from its outer atmosphere. Observations with Yohkoh satellite showed that all the sporadic heating from large flares to ubiquitous tiny bursts in the solar corona is due to magnetic reconnection. Magnetic fields do dissipate in the solar corona with a time scale 10(12) faster than that of the classical Ohmic dissipation. Though this leads to an attractive conjecture that the solar corona is heated by nano-bursts as initially proposed by Gene Parker, the precise mechanism for the heating the solar corona and chromosphere is not known. These activities on the surface of the star are driven by magnetic fields created by internal dynamo mechanism. The magnetic field strength on the surface of the Sun exceeds 1kG, while that at the bottom of the convection zone may exceed 100kG. They are too strong, far stronger than the equi-partition magnetic field strength. Any dynamo mechanism can amplify field strength upto the equi-partition field strength, but we had not known a mechanism to produce field strength beyond that threshold. The concept of Hinode satellite is that two X-ray and EUV telescopes observe the dissipation part of the magnetic life-cycle, while the visible light telescope simultaneously observes the generation and transport of magnetic field. Discoveries with Hinode include transverse MHD waves, local dynamo process in the convection zone, convective collapse resulting in super equi-partition magnetic field strength, emergence of large-scale flux rope from below the photosphere, kG-magnetic patches in the polar regions, identification of the origin of slow solar wind, and enigmatic fine-scale flows in the prominence. I will present and discuss how some of these new results from Hinode are probing fundamental physical processes that will have applications in many other scenarios across the universe. Finally, I will introduce SOLAR-C and SOLAR-D missions with our roadmap in solar and helio-physics. |