On July 11, The Astrophysical Journal published the latest work conducted by the graduate student CHEN Yuhao, Dr. YE Jing and Dr. MEI Zhixing from Yunnan Observatories (YNAO) and other co-authors. They performed Magnetohydrodynamic (MHD) simulations to study how the newly emerging flux triggers the catastrophe of coronal magnetic configuration, which may explain the transverse motion of filaments.
Solar eruption is the most energetic event in the solar system, in which up to 1032 ergs of magnetic energy is released. The catastrophe theory is one of the main mechanisms responsible for the solar eruption, which describes the loss of equilibrium of a pre-existing filament in the stable coronal magnetic fields. In the last 20 years, Professor Lin from YNAO figured out the first analytic solution for the catastrophic model driven by the newly emerging flux, but it is too simplified. Thus, a detailed study of the catastrophic process in a more realistic condition is eagerly desired.
Researchers performed 2D MHD numerical experiments to study the response of the coronal magnetic configuration to the newly emerging magnetic flux. The configuration includes an electric-current-carrying flux rope modeling the prominence floating in the corona and the background magnetic field produced by two separated magnetic dipoles embedded in the photosphere. The global configuration shows asymmetry. Their results indicate that the flux rope of a small radius can self-regulate to the equilibrium position and it evolves quasi-statically until the flux rope reaches the critical point, where the catastrophe occurs. But the flux rope of a large radius doesn’t have an equilibrium position.
In the catastrophic process, two different current sheets (CSs) are formed. One is located under the rising flux rope, and the other one is formed due to magnetic reconnection between flux rope and the background magnetic fields. These CSs affect continuously the force balance of the flux rope, and result in a horizontal displacement.
This research helps us better understand the complex solar eruption mechanism, especially for the transverse motion of solar filaments or non-radial eruptions.
Contact:
YE Jing
Yunnan Observatories, CAS
Email: yj@ynao.ac.cn
