The Astrophysical Journal Letters recently published a paper based on the high-resolution data taken by the ground-based New Vacuum Solar Telescope (NVST) and the space-borne Solar Dynamic Observatory (SDO), which was performed by researchers from Yunnan Observatories of Chinese Academy of Sciences and Harbin Institute of Technology. The authors found that the Kelvin-Helmholtz Instability occurred at the interface between cold and hot plasma flows can heat the local plasma to coronal temperature.

The Kelvin-Helmholtz instability can occur when there is velocity shear in a single continuous fluid, or where there is a velocity difference across the interface between two fluids. It can mix plasma components of different properties and convert dynamic fluid energy from large-scale structure to small ones.

Using the high-resolution observations taken by the NVST and SDO, the authors analyzed a small plasma eruption on 2017 September 9 that showed obvious Kelvin-Helmholtz instability. The results show that the instability occurred at the interface between cold and hot plasma flows, and the sudden heating of the local plasma to the coronal temperature during the period of the instability was confirmed.

Because small-scale eruptive phenomena are ubiquitous in the solar atmosphere, therefore, the occurrence of Kelvin-Helmholtz instability should also everywhere. So, the authors further conclude that Kelvin-Helmholtz instability could occur at a variety of length scales and could contribute to plasma heating.

Contact:

SHEN Yuandeng,Yunnan Observatories, CAS

ydshen@ynao.ac.cn