scostep 2010 (stp12) - Leibniz-Institut für Atmosphärenphysik an der ...

STP12 Abstracts
Berlin, 12 - 16 July 2010
SCOSTEP Symposium 2010
Data-driven Modeling of Solar Storm
Kusano Kanya 1 , Yamamoto Tetsuya T. 1 , Inoue Satoshi 2 , Shiota Daiko 3 , Nishida Keisuke 4 , Kataoka
Ryuho 5
1 Solar-Terrestrial Environment Laboratory, Nagoya University, 2 National Institute of Information
and Communications Technology, 3 RIKEN, 4 Kwasan Observatory, Kyoto University, 5 Interactive
Research Center of Science, Graduate School of Science and Engineering, Tokyo Institute of
Technology
Solar storm caused by solar flare and/or coronal mass ejection (CME) is major source of
heliospheric and geo-magnetospheric disturbance. However, the onset mechanism of that is
not well understood yet. Aiming at revealing the initiation mechanism of solar storm, we have
recently developed a new data-driven simulation model based on the observation by Solar
Optical Telescope (SOT) onboard Hinode solar physics satellite. Our model consists of the
following three different magnetohydrodynamic (MHD) simulations for solar flare, CME, and
ICME, respectively. For the flare model, we first calculated the nonlinear force-free field
(NLFFF) of active region NOAA 10930 using the vector magnetogram observed by
Hinode/SOT as the boundary condition, and carried out the three-dimensional MHD
simulation by imposing photospheric variation which corresponds to the magnetic flux
emerging activity seen in the active region prior to the flare occurred on December 13, 2006.
As a result, we have successfully simulated a solar eruption, in which magnetic reconnection
drives super Alfvenic plasma jet from the flaring site. It was also shown that magnetic
reconnection may initiate the transfer of magnetic helicity out of the active region into a large
scale magnetic loop. Second, we handed over the result of the flare model into the global
corona model, and restarted the simulation for CME formation process. As a result, it was
shown that the magnetic loop, which was subject to the magnetic helicity injection due to the
flaring reconnection, could expand to a CME. Finally, we have performed the interplanetary
space simulation, in which the CME with magnetic helicity was set on the inner boundary.
The model successfully tracked the propagation of ICME up to the orbit of earth, and
simulated the variation of magnetic field and velocity consistent with the in-situ observation
by ACE satellite. All the results indicate that the series of data-driven simulations is a
powerful tool for understanding the entire process of solar storm. It also suggests that the
process from flare to ICME should not be explained as a result of simple plasmoid ejection
but is constituted of several stages, which might be governed by different processes of
resistive and ideal MHD.