2006 Fiscal Year Final Research Report Summary
Study of Magnetic Helicity Dynamics in Solar and Space Plasmas
| Project/Area Number |
16540216
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Astronomy
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| Research Institution | Independent Administrative Institution, Japan Agency for Marine-Earth Science and Technology |
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Principal Investigator |
KUSANO Kanya Japan Agency for Marine-Earth Science and Technology, The Earth Simulator Center, Program Director, 地球シミュレータセンター, プログラムデイレクター (70183796)
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| Co-Investigator(Kenkyū-buntansha) |
MIYOSHI Takahiro Hiroshima University, Graduate School of Science, Department of Physics, Assistant Professor, 大学院・理学研究科, 助手 (60335700)
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| Project Period (FY) |
2004 – 2006
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| Keywords | magnetic helicity / the solar corona / space plasma / flare / CME / MHD / HLLD / magnetosohere |
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| Research Abstract |
Magnetic helicity is a physical variable, which can quantify the total linking number of magnetic field flux. Since magnetic helicity is a conserved quantity in the ideal magnetohydrodynamic (MHD) process, and is a proxy of magnetic free energy, it is widely believed that magnetic helicity may play a role as tracer and driver of MHD activities. We have investigated the dynamics of magnetic helicity in the Sun-Earth connection system. First, we have developed the methodology to measure magnetic helicity flux across the solar surface based on the madnetogram observation, and found that the helicity injection into the solar corona is well correlated with the soft X-ray emission activity in the solar corona. Second, we have developed the new numerical tool to reconstruct the three-dimensional magnetic field in the solar corona from vector magnetogram, and applied it to the data provided by the new solar satellite observatory HINODE.. As a result, we have revealed that magnetic field in pre-flare phase indeed has a sheared structure, which is well consistent with the paring of two-ribbon appearing after the onset of flare. Third, we created the state-of-the-art numerical scheme for ideal MHD equation, called HUD scheme, and have demonstrated that the computational performance of HLLD scheme is better than any previous schemes for the accuracy, robustness, efficiency and handiness of computation. Finally, we have applied the HLLD scheme to the solar coronal simulation, which fully includes the spherical geometry, as well as to the magnetospheric simulation, in which more generic equation of state is taken into account. The solar coronal simulation has revealed that the critical magnetic helicity to drive the onset of coronal mass ejection (CME) is sensitive to the spatial structure of magnetic helicity injection.
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[Journal Article] Macro-Micro Interlocked Simulation for Multiscale Phenomena2007
Author(s)
Kusano, K., Hirose, S., Sugiyama, T., Shima, S., Kawano, A., Hasegawa, H.
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Journal Title
Advancing Science and Society through Computation (in Lecture Notes in Computational Science and Engineering, Springer) (in press)
Description
「研究成果報告書概要(欧文)」より
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[Journal Article] Macro-Micro Interlocked Simulation for Multiscale Phenomena
Author(s)
Kusano, K., Hirose, S., Sugiyama, T., Shima, S., Kawano, A., Hase gawa, H.
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Journal Title
"Advancing Science and Society through Computation" in Lecture Notes in Computational Science and Engineering (Sprinaer) 2007 (in press)
Description
「研究成果報告書概要(和文)」より
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