Characteristics of EUV Coronal Jets Observed with STEREO/SECCHI

Abstract

In this paper we present the first comprehensive statistical study of EUV coronal jets observed with the SECCHI (Sun Earth Connection Coronal and Heliospheric Investigation) imaging suites of the two STEREO spacecraft. A catalogue of 79 polar jets is presented, identified from simultaneous EUV and white-light coronagraph observations, taken during the time period March 2007 to April 2008, when solar activity was at a minimum. The twin spacecraft angular separation increased during this time interval from 2 to 48 degrees. The appearances of the coronal jets were always correlated with underlying small-scale chromospheric bright points. A basic characterization of the morphology and identification of the presence of helical structure were established with respect to recently proposed models for their origin and temporal evolution. Though each jet appeared morphologically similar in the coronagraph field of view, in the sense of a narrow collimated outward flow of matter, at the source region in the low corona the jet showed different characteristics, which may correspond to different magnetic structures. A classification of the events with respect to previous jet studies shows that amongst the 79 events there were 37 Eiffel tower-type jet STEREO events, commonly interpreted as a small-scale (∼35 arc sec) magnetic bipole reconnecting with the ambient unipolar open coronal magnetic fields at its loop tops, and 12 lambda-type jet events commonly interpreted as reconnection with the ambient field happening at the bipole footpoints. Five events were termed micro-CME-type jet events because they resembled the classical coronal mass ejections (CMEs) but on much smaller scales. The remaining 25 cases could not be uniquely classified. Thirty-one of the total number of events exhibited a helical magnetic field structure, indicative for a torsional motion of the jet around its axis of propagation. A few jets are also found in equatorial coronal holes. In this study we present sample events for each of the jet types using both, STEREO A and STEREO B, perspectives. The typical lifetimes in the SECCHI/EUVI (Extreme UltraViolet Imager) field of view between 1.0 to 1.7 R and in SECCHI/COR1 field of view between 1.4 to 4 R are obtained, and the derived speeds are roughly estimated. In summary, the observations support the assumption of continuous small-scale reconnection as an intrinsic feature of the solar corona, with its role for the heating of the corona, particle acceleration, structuring and acceleration of the solar wind remaining to be explored in more detail in further studies.

Dynamics and plasma properties of an X-ray jet from SUMER, EIS, XRT, and EUVI A & B simultaneous observations

“…The authors depicted a helical structure of a jet, which showed signs of untwisting with the jet initially ascending slowly with ≈10−20 km s −1 and then suddenly accelerating to velocities higher than 300 km s −1 . Helical structures in jets have also been reported by Shimojo et al (1996), Jiang et al (2007), and Nisticò et al (2009). Kamio et al (2010) studied the relation of so-called macrospicules in He ii 304 Å and an X-ray jet.…”

A Breakout Model for Solar Coronal Jets with Filaments

“…Jets occur prolifically across the solar surface, most notably within coronal holes and around the periphery of active regions (Shimojo et al 1996;Savcheva et al 2007). They are observed in X-rays (e.g., Shimojo et al 1996;Cirtain et al 2007) and at a variety of extreme-ultraviolet (EUV) wavelengths (e.g., Nisticò et al 2009;Zhang et al 2016), reflecting the fact that some jets possess both hot and cool (relative to the ambient corona) components. Some jets are energetic enough to reach the heliosphere and become visible as jet-like coronal mass ejections (CMEs) in white-light coronagraphs (e.g., Wang et al 1998;Patsourakos et al 2008;Hong et al 2011;Moore et al 2015).…”

Physical properties of solar polar jets

“…Using the Solar Terrestrial Relations Observatory (STEREO; Kaiser et al 2008) twin inner coronagraphs (COR1; Thompson et al 2003) Nisticò et al (2009 studied various aspects of jets, including their correlation with underlying small scale chromospheric bright points. More recently, Pucci et al (2012) have presented an analysis of the correlation of X-ray bright points and jets observed by Hinode/XRT and concluded that most of the jets occurred in close temporal association with the brightness maximum in bright points.…”