Thumbnail
Access Restriction
Open

Author Xiaozhou, Zhao ♦ Gan, Weiqun ♦ Xia, Chun ♦ Keppens, Rony
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword ASTROPHYSICS, COSMOLOGY AND ASTRONOMY ♦ ACCELERATION ♦ CHROMOSPHERE ♦ EQUILIBRIUM ♦ EVOLUTION ♦ FORCE-FREE MAGNETIC FIELDS ♦ INSTABILITY ♦ LEVITATION ♦ LORENTZ FORCE ♦ MAGNETIC FLUX ♦ MAGNETIC PROPERTIES ♦ MAGNETIC RECONNECTION ♦ MAGNETOHYDRODYNAMICS ♦ MASS ♦ PHASE TRANSFORMATIONS ♦ SIMULATION ♦ SUN
Abstract In this paper, we study how a flux rope (FR) is formed and evolves into the corresponding structure of a coronal mass ejection (CME) numerically driven by photospheric converging motion. A two-and-a-half-dimensional magnetohydrodynamics simulation is conducted in a chromosphere-transition-corona setup. The initial arcade-like linear force-free magnetic field is driven by an imposed slow motion converging toward the magnetic inversion line at the bottom boundary. The convergence brings opposite-polarity magnetic flux to the polarity inversion, giving rise to the formation of an FR by magnetic reconnection and eventually to the eruption of a CME. During the FR formation, an embedded prominence gets formed by the levitation of chromospheric material. We confirm that the converging flow is a potential mechanism for the formation of FRs and a possible triggering mechanism for CMEs. We investigate the thermal, dynamical, and magnetic properties of the FR and its embedded prominence by tracking their thermal evolution, analyzing their force balance, and measuring their kinematic quantities. The phase transition from the initiation phase to the acceleration phase of the kinematic evolution of the FR was observed in our simulation. The FR undergoes a series of quasi-static equilibrium states in the initiation phase; while in the acceleration phase the FR is driven by Lorentz force and the impulsive acceleration occurs. The underlying physical reason for the phase transition is the change of the reconnection mechanism from the Sweet–Parker to the unsteady bursty regime of reconnection in the evolving current sheet underneath the FR.
ISSN 0004637X
Educational Use Research
Learning Resource Type Article
Publisher Date 2017-06-01
Publisher Place United States
Journal Astrophysical Journal
Volume Number 841
Issue Number 2


Open content in new tab

   Open content in new tab