HR: 1330h
AN: SH42B-0512 [PDF]
TI: The role of flux emergence as a driver of coronal mass ejections
AU: * Magara, T
EM: magara@nrl.navy.mil
AF: Naval Research Laboratory, Code 7675, Washington DC, DC 20375-5352 United States
AU: Antiochos, S K
EM: antiochos@nrl.navy.mil
AF: Naval Research Laboratory, Code 7675, Washington DC, DC 20375-5352 United States
AU: Luhmann, J G
EM: jgluhman@ssl.berkeley.edu
AF: Space Sciences Laboratory, University of California, Berkeley, 7 Gauss Way, 7 Gauss Way, CA 94720-7450 United States
AB:
Recently it has been suggested that coronal mass ejections (CMEs) are closely related to the interaction between different
magnetic domains formed in the corona. For example, a so-called breakout model of CMEs shows that a core domain field which
is enhanced by shearing motions in the photosphere interacts with the overlying field, and this weakens the confining effect
of the overlying field and eventually enables the core domain field to erupt outwards. In this study, we take the
subphotospheric dynamics into this model and see how flux emergence affects the breakout process. Our work is based on
3-dimensional resistive MHD simulations in which we initially set a potential bipolar field above the photosphere and place a
magnetic flux tube below the photosphere. The flux tube then emerges into the photosphere and starts to interact with the
bipolar field. As the flux tube expands into the corona, a current layer develops around the interface between emerging
magnetic field and preexisting coronal field. We focus on its structure and evolution because that current layer plays a
crucial role in a breakout of emerging magnetic field. To see this, we apply a locally enhanced resistivity around the
current layer and study the magnetic reconnection between emerging field and preexisting field.
DE: 7500 SOLAR PHYSICS, ASTROPHYSICS, AND ASTRONOMY
DE: 7513 Coronal mass ejections
DE: 7800 SPACE PLASMA PHYSICS
DE: 7835 Magnetic reconnection
DE: 7843 Numerical simulation studies
SC: SPA - Solar and Heliospheric Physics [SH]
MN: 2003 Fall Meeting