In the latest work published on The Astrophysical Journal on July 11, graduate student CHEN Yuhao, Dr. YE Jing and Dr. MEI Zhixing from the Yunnan Observatories (YNAO) of the Chinese Academy of Sciences performed Magnetohydrodynamic (MHD) simulations to investigate 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, releasing up to 10³² ergs of magnetic energy. 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. 

Over the past 20 years, Prof. LIN Jun of YNAO clarified 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.

In this study, the researchers performed two-dimensional 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 a 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 an equilibrium position and it evolves quasi-statically until the flux rope reaches the critical point, where the catastrophe occurs. But there is no equilibrium position for the large radius flux rope.

According to the researchers, during the catastrophic process, two different current sheets (CSs) are formed. One is under the rising flux rope, and the other one is formed due to magnetic reconnection between the flux rope and the background magnetic fields. These CSs continue to affect the force balance of the flux rope and cause horizontal displacement.

This study helps to better understand the complex solar eruption mechanism, especially the transverse motion of solar filaments or non-radial eruptions.