1. Merging of coronal and heliospheric numerical two-dimensional MHD models D. Odstrcil, et al., J. Geophys. Res., 107, 2002. 2004 年 10 月 14 日 太陽雑誌会 ( 速報 ) 西田

2. Introduction Space weather research involves a chain of various phenomena occurring simultaneously on different spatial and temporal scales. An integrated modeling approach is necessary for space weather research. This paper presents a demonstration of merged coronal and heliospheric 2-D MHD models.

3. Numerical Models Coronal Model –2-D axisymmetric resistive MHD equations –Semi-implicit finite difference scheme using staggered values Heliospheric Model –2-D axisymmetric ideal MHD equations –Explicit finite difference total-variation- diminishing high-resolution Lax-Friendrichs (TVDLF) scheme using cell-centered values

4. Merged numerical grid Fig. 1 Coronal Model –200x300 grid points –Nonuniform mesh for the streamer Heliospheric Model –340x240 grid points The output from the coronal model is used as a boundary condition for the heliospheric solutions

5. Fig. 2 Ambient State in the corona

6. Fig. 3 Ambient State in the heliosphere

7. Fig. 4. Blue: 70°, Red: 80°, Black: 90°

8. Transient Disturbances The streamer products strongly sheared field lines that are nearly aligned with the neutral line; it is just a convenient mechanism. The sharing phase lasts 5.2 days. We reduce the magnetic flux at the photosphere to create a flux rope. After ~18 hours the arcade erupts.

9. http://sprg.ssl.berkeley.edu/cism/

10. Fig. 5

11. Fig. 6. Blue: 70°, Red: 80°, Black: 90°

12. Fig. 7

13. Fig. 8

14. Fig. 9

15. Fig. 10. Blue: 70°, Red: 80°, Black: 90°

16. Conclusions (1/2) The merging of coronal and heliospheric MHD models has been successfully implemented for a 2-D ambient state and a transient disturbance. Different mathematical models, numerical methods, and computational grids were used in this work, and thus the merging of the numerical models was demonstrated for a quote general case.

17. Conclusions (2/2) Merged coronal and heliospheric models have enabled the simulation of transient disturbances. The solar wind and magnetic parameters at 1 AU resulting from the coupled computations can provide input for geo- effectivity models.

18. Fig. A1