The energetic expulsions of the sun’s organized magnetic properties are known as coronal mass ejections (CMEs). A possible connection between CMEs, solar flares and geomagnetic disturbances can be established through studies of CME quasi-periodicity.

If CMEs with variable geomagnetic efficiency have different periods, this can be determined by looking at the quasi-periodicity of the CMEs with different angular widths.

Researchers from the Yunnan Observatories of the Chinese Academy of Sciences (CAS), led by Prof. DENG Linhua, classified the CMEs from January 1, 1996 to August 31, 2021 by angular latitude. Their collaborators at Guangzhou University systematically examined the quasi-periodic variations corresponding to CMEs of different angular latitudes in the northern and southern hemispheres.

The team examined the quasi-periodicity of CMEs with different angular widths based on CME occurrence rate using the latest Coordinated Data Analysis Workshops (CDAW) catalog. Four categories of CMEs were identified: narrow, typical, partial halo, and halo. Researchers found that there were, in fact, different periods for CMEs with different angular widths, including the Rieger-type periodicity, the ten rotations, and the quasi-biennial oscillations.

prof. DENG said: “The occurrence of CMEs shows statistically significant short- and medium-range oscillations characterized by different periodicity, intermittency and asymmetric development in the northern and southern hemispheres of the Sun.”

The activity of solar flares, solar wind, interplanetary magnetic field and geomagnetic activity have all been associated with the quasi-periodicity of the CMEs discovered in this study. Consequently, the oscillations in coronal magnetic activity, solar flare outbursts and interplanetary space should be connected through the quasi-periodic variations of the CMEs.

prof. DENG said: “Our study may help understand how magnetic energy is built, stored and released in magnetic flux systems, the origin and formation process of CMEs, which are essential for solar physicists to reveal the magnetic activity cycle and predict catastrophic space weather.”

Magazine reference:

  1. Xia Li, Hui Deng et al. Quasiperiodic variations of coronal mass ejections with different angular widths. The Astrophysical Journal. DOI 10.3847/1538-4365/acb431