JAXA Supercomputer System Annual Report April 2018-March 2019

Report Number: R18EU0912

Subject Category: Space and Astronautical Science

PDF available here

• Responsible Representative: Yoshifumi Saito, Institute of Space and Astronautical Science, Department of Solar System Sciences
• Contact Information: Toshifumi Shimizu (shimizu.toshifumi@jaxa.jp)
• Members: Yusuke Kawabata, Toshifumi Shimizu, Takahiro Hasegawa

Abstract

Our study focuses on understanding of the mechanism responsible for the occurrence of solar flares. We derive 3D magnetic field structure in the corona by performing a 3D magnetohydrodynamics simulation using vector magnetic field map acquired with the Hinode spacecraft. We investigate the relation between 3D magnetic field structure and the occurrence of solar flares.

Reference URL

Please refer to ‘ひのでプロジェクトのホームページ:TOP PAGE‘.

Reasons for using JSS2

We perform 3D magnetohydrodynamics numerical simulation by using vector magnetic field data acquired with the Hinode spacecraft in order to infer 3D magnetic field structure in the corona. We need large computational resource in order to perform three-dimensional magnetohydrodynamics simulation.

Achievements of the Year

Nonlinear force-free field (NLFFF) modeling is a strong tool to infer the three-dimensional magnetic field in the solar corona, where the force-free approximation is valid. If we give the magnetic field observed in the photosphere as a boundary condition, we can solve this nonlinear equation. However, Gary (2002) argued that the magnetic field in the photosphere does not satisfy the condition of the force-free. This year we try to obtain the chromospheric magnetic field (1000 km above the photosphere) with spectropolarimetric observations and compared it with the magnetic field dervied by the NLFFF modeling from the photsphere. Our analysis shows that there is more twisted magnetic field in the chromosphere than the NLFFF estimated as shown in Figure 1.

Fig.1: Gray scale:The vertical component of the magnetic field to the solar surface. Green arrows: Horizontal magnetic field. Upper left: Photospheric magnetic field in the active region observed with Hinode. Upper right: Potential magmetic field extrapolated from the photosphere. Bottom left: NLFFF extrapolated from the photopshere. Bottom right: Chromospheric magnetic field observed with VTT

Publications

– Peer-reviewed papers

Y. Kawabata, T. Miura, Y. Watanabe, Y. Ike, Y. Ema, T. Kemmochi, S. Matsubara, T. Yoneda, Y. Tiba, and T. Kashiwabara, “Initial Condition Dependency of Magnetohydrodynamics Relaxation Method: Spatial Distribution of Force-Free Alpha”, LMSR 2018

– Oral Presentations

T. Hasegawa, T. Shimizu, “Observational Study on Magnetic Helicity Injected by Self and Mutual Rotations”, JpGU, Chiba, May-2018

Y. Kawabata, S. Inoue, T. Shimizu, “Extrapolation of three-dimensional magnetic field structure in flare-productive active region with different initial condition”, JpGU, Chiba, May-2018

T. Hasegawa, T. Shimizu, “Observational Study on Magnetic Helicity Injected by Self and Mutual Rotations”, Hinode-12 Science Meeting, Granada, September-2018

Y. Kawabata, A. Asensio Ramos, S. Inoue, T. Shimizu, “Chromospheric magnetic field: A comparison of He I 10830 A observation with nonlinear force-free field extrapolation”, Hinode-12 Science Meeting, Granada, September-2018

Usage of JSS2

Computational Information

• Process Parallelization Methods: MPI
• Thread Parallelization Methods: N/A
• Number of Processes: 1 – 192
• Elapsed Time per Case: 20 Hour(s)

Resources Used

Fraction of Usage in Total Resources*1(%): 0.20

Details

Please refer to System Configuration of JSS2 for the system configuration and major specifications of JSS2.

*1: Fraction of Usage in Total Resources: Weighted average of three resource types (Computing, File System, and Archiver).

*2: Fraction of Usage：Percentage of usage relative to each resource used in one year.

JAXA Supercomputer System Annual Report April 2018-March 2019