Dr. WANG Jincheng and his collaborators from Yunnan Observatories (YNAO), Chinese Academy of Sciences (CAS), have conducted a detailed study of solar prominences using data from the one-meter New Vacuum Solar Telescope (NVST) and the Chinese Hα Solar Explorer (CHASE). Their findings, investigating the physical nature of small-scale oscillations in prominences and their contribution to coronal heating, were recently published in the special issue of The Astrophysical Journal Letters focused on Early Results from the CHASE Mission.

Solar prominences display a variety of complex fine structures and dynamic processes, including vertical structures, oscillatory phenomena, transverse horizontal motions, bubbles at the base, and upflow plumes. These features play a key role in understanding the structure of solar prominences. Due to the limited availability of high temporal and spatial resolution observational data, research in this area is still in its early stage, and many physical processes remain unexplained.

The high temporal-spatial resolution observational data from NVST, currently the world’s best ground-based telescope for imaging solar limb prominences, have enabled the study of these fine structures and dynamics. The CHASE offers unique spectral observation capabilities for solar prominences. The researchers extensively studied the wave phenomena occurring in the vertical threads within prominences using data from these two Chinese solar telescopes. 

It was found that during the ascent of prominences, the vertical threads exhibited transverse oscillations accompanied by the upwelling material flow. These oscillations had periods ranging from 13 to 16 minutes, amplitudes of approximately 0.6 Mm, and velocity amplitudes of 3-4 km/s, indicating small-scale oscillations.

Furthermore, the researchers observed that the amplitudes, wavelengths, and periods of these oscillations amplified over time during propagation, and their phase velocities were comparable with the upward material flow. This phenomenon suggests negative-energy wave instability. Based on prominence seismology and observational characteristics, the magnetic field of the vertical threads was estimated to be 1-3 Gauss with an inclination angle of 31 degrees relative to the plane of the sky. It has been estimated that the energy carried by these transverse oscillations is not sufficient for coronal heating.

This research sheds light on the dynamics and magnetic characteristics of solar prominences, enriching our comprehension of their behavior within the solar atmosphere. This achievement was a collaborative effort involving scholars from YNAO, Purple Mountain Observatories of CAS Nanjing University, and National Astronomical Observatories of China.

Contact:
WANG Jincheng
Yunnan Observatories, CAS
e-mail: wangjincheng@ynao.ac.cn