Title: 

CORONAL MASS EJECTIONS: THEORY AND MODELING

Ilia Roussev
University of Michigan


Abstract:

Coronal mass ejections (CMEs), and the solar energetic particle
events associated with them, constitute one of the major hazards for
spacecraft in the inner solar system. Particularly important in this
regard are the high-energy ($> 100$~MeV) protons, which can appear
within as short a span of time as 20 minutes after the onset of the
solar eruption.

CMEs and solar flares are now recognized to be different
manifestations of a single physical process, which involves a major
disruption of coronal magnetic fields. Any model attempting to
explain solar eruptions has to account for two basic properties of
eruptive processes: fundamental cause of the eruption itself; and
nature of morphological features that form and develop in the
eruptive process. Recent theories suggest that a catastrophic loss
of mechanical equilibrium in coronal magnetic fields constitutes a
fairly promising mechanism for triggering solar eruptions.

One of the principle aims of our research is the development of
numerical models which account for the onset and evolution of
coronal mass ejections.  Once perfected, such models should lead to
significant improvements in our ability to forecast solar eruptions
before they start. By constructing a fully three-dimensional
numerical model, which incorporates solar magnetic field data and a
loss-of-equilibrium mechanism, we have been able to model a
realistic CME event, and determine that a shock wave can develop
close to the Sun sufficiently strong to account for the energization
of solar protons up to kinetic energies of 2~GeV.
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