Observational study on the fine structure and dynamics of a solar jet. I. Energy build-up process around a satellite spot

Abstract

We report a solar jet phenomenon associated with successive flares on November 10th 2014. These explosive events were involved with the satellite spots' emergence around a δ-type sunspot in the decaying active region NOAA 12205. The data of this jet was provided by Solar Dynamics Observatory (SDO), X-Ray Telescope (XRT) aboard Hinode, Interface Region Imaging Spectrograph (IRIS) and Domeless Solar Telescope (DST) at Hida Observatory, Kyoto University. These plentiful data enabled us to present this series of papers to discuss the entire processes of the observed phenomena including the energy storage, event trigger, and energy release. In this paper, we focus on the energy build-up and trigger phases, by analyzing the photospheric horizontal flow field around the active region with an optical flow method. The analysis reveals the following three. (i) The observed explosive phenomena involved three satellite spots, the magnetic fluxes of which successively reconnected with their pre-existing ambient fields. (ii) All of these satellite spots emerged in the moat region of a pivotal δ-type sunspot, especially near its convergent boundary with the neighboring supergranules or moat regions of adjacent sunspots. (iii) Around the jet ejection site, the positive polarities of satellite spot and adjacent emerging flux encountered the global magnetic field with negative polarity in the moat region of the pivotal δ-type sunspot, and thus the polarity inversion line was formed along the convergent boundary of the photospheric horizontal flow channels.

Observation and modelling of solar jets

“…Roy [21] confirmed this finding and further proposed that significant magnetic flux change over a short time interval is also important for producing surges. Subsequent studies based on high-resolution observations revealed that evolving satellite sunspots are liable to launch recurrent jets through continuous collisions with the main sunspots [55,[88][89][90][91][92][93][94]. In quiet-Sun and coronal hole regions, small opposite-polarity magnetic elements can be recognized as the most conspicuous photospheric progenitor for many lower-energy, smallscale coronal jets.…”

Observation and Modeling of Solar Jets

“…Roy [21] confirmed this finding and further proposed that significant magnetic flux change over a short time interval is also important for producing surges. Subsequent studies based on high resolution observations revealed that the appearance of evolving satellite sunspots are liable to launch recurrent jets through continuously collision with the main sunspots [55,[88][89][90][91][92][93][94]. In quiet-Sun and coronal hole regions, small opposite-polarity magnetic elements can be recognized as the most conspicuous photospheric progenitor for many lower-energy, small-scale coronal jets.…”

The Trigger Mechanism of Recurrent Solar Active Region Jets Revealed by the Magnetic Properties of a Coronal Geyser Site

“…By combining modeling and observations, Cheung et al (2015) analyzed 4 jets originating from a pore embedded in the interior of a supergranule to obtain data-driven simulations that show that the emergence of magnetic field structures in the vicinity of a pore are compatible with recurrent jet formation. A recent case study, presented by Sakaue et al (2017Sakaue et al ( , 2018 showed that such flux emergence plays a significant role in producing one EUV AR jet.…”