Numerical simulations of the breakout model for the initiation of solar coronal mass ejections and in-situ observations of their interplanetary structure.

摘要

Coronal mass ejections (CMEs) are the one of the most exciting manifestations of dynamic solar activity and one of the most important solar inputs into the Sun-Earth system. Utilizing both large-scale numerical magnetohydrodynamics (MHD) simulations of solar eruptions and in-situ magnetic field and plasma measurements by satellites, substantial progress is made on a number of outstanding scientific questions about the origin, structure, and long-term heliospheric effects of CMEs.; We present results of the first successful demonstration of the breakout model for CME initiation in 3-dimensions. The 3D topology allows for the gradual accumulation of free magnetic energy and magnetic reconnection external to the highly-sheared filament channel, which triggers catastrophic, runaway expansion and leads to the eruption of the low-lying sheared flux. Previous 2.5D breakout simulations are examined in an observational context. There is excellent agreement between the simulation results and CME morphology and dynamics through the corona, the properties of eruptive flare loop systems, and in the ejecta magnetic structure and in-situ measurements of the most coherent interplanetary CMEs.; The magnetic and plasma structure of the most ordered interplanetary CMES (ICMEs, also called magnetic clouds) is examined using field and plasma data from the WIND and ACE spacecraft. We find anomalously high charge states of heavy ion species present, on average, throughout the entire magnetic cloud which suggests enhanced heating close to the sun, most-likely associated with eruptive flare magnetic reconnection. A long-term study of magnetic clouds events from 1995--2003 is also presented and the magnetic flux and helicity content is analyzed for solar-cycle trends. Magnetic clouds show a solar-cycle evolution of the preference for right-handed fields during the cycle 23 solar minimum that changes to a left-handed preference during solar maximum. A time varying dynamo-type source is present for at least some fraction of ICME magnetic helicity content.; Future work involves extending the new 3D breakout results to increasingly realistic solar environments, with the ultimate goal of quantitative model-data comparisons for a complete understanding, forward-modeling, and eventual prediction of coronal mass ejections.