Quasi-periodic fast-propagating (QFP) waves and Extreme-ultraviolet (EUV) waves are two common waves in solar atmosphere. The origins of these fluctuations have been debated over the past few decades. Researchers suggest that they could be triggered by either a flare pulse or a coronal mass ejection (CME). EUV waves are now thought to be caused by CMEs, but the origin of QFP waves is thought to be caused by flare pressure pulses.

However, MIAO Yuhu et al. of the Yunnan observatories, Chinese Academy Sciences, discovered a quite different and interesting phenomenon. In the 2011 March 10 solar activity eruption event(flare/CME), a QFP wave and a EUV wave were generated simultaneously. The first wavefront of the QFP wave train was the same as the wavefront of EUV wave. The paper has been published in the American journal of The Astrophysical Journal Letters.

This event provides a good opportunity for us to study the trigger mechanism of the QFP wave and the EUV wave in depth. Since the front of QFP wave and EUV wave are the same wave train, and STEREO satellite has also confirmed corresponding CME, MIAO et al. believe that QFP waves can be excited by CMEs.

During the eruption, the initial broadband pulse can be dispersed and evolve into multiple wave train of the QFP. Their study showed that the shock wave, which is piston-driven by broadband pulse, can further evolve into QFP wave along the funnel-like coronal loops. In this event, both flare and CME were observed.

In short, the conclusion of their study on this event is that CME eruption caused it. However, researchers need to study more cases and prove which of the two(flare/CME) is the real trigger mechanism.

Contact:

LIU Yu

lyu@ynao.ac.cn

Coronal Observation and Siting Technology Group, YNO