Speaker
Huadong Chen
(National Astronomical Observatories, Chinese Academy of Sciences)
Description
Triggering mechanisms of solar eruptions have long been a challenge. A few previous
case studies have indicated that preceding gentle filament merging via magnetic
reconnection may launch following intense eruption, according to the tether-cutting
(TC) model. However, the detailed process of TC reconnection between filaments has
not been exhibited yet. In this work, we report the high-resolution observations from
the Interface Region Imaging Spectrometer (IRIS) of TC reconnection between two
sheared filaments in NOAA active region 12146. The TC reconnection commenced on
∼15:35 UT on 2014 August 29 and triggered an eruptive GOES C4.3-class flare ∼8
minutes later. An associated coronal mass ejection appeared in the field of view of
the Solar and Heliospheric Observatory/LASCO C2 about 40 minutes later. Thanks to the
high spatial resolution of IRIS data, bright plasma outflows generated by the TC
reconnection are clearly observed, which moved along the subarcsecond fine-scale flux
tube structures in the erupting filament. Based on the imaging and spectral
observations, the mean plane-of-sky and line-of-sight velocities of the TC
reconnection outflows are separately measured to be ∼79 and 86 km s−1, which derives
an average real speed of ∼120 km s−1. In addition, it is found that spectral
features, such as peak intensities, Doppler shifts, and line widths in the TC
reconnection region are evidently enhanced compared to those in the nearby region
just before the flare.
Primary author
Huadong Chen
(National Astronomical Observatories, Chinese Academy of Sciences)