Dichotomy of Solar Coronal Jets: Standard Jets and Blowout Jets

Abstract

examining many X-ray jets in Hinode/XRT coronal X-ray movies of the polar coronal holes, we found that there is a dichotomy of polar X-ray jets. About two thirds fit the standard reconnection picture for coronal jets, and about one third are another type. We present observations indicating that the non-standard jets are counterparts of erupting-loop Hα macrospicules, jets in which the jet-base magnetic arch undergoes a miniature version of the blowout eruptions that produce major CMEs. From the coronal X-ray movies we present in detail two typical standard X-ray jets and two typical blowout X-ray jets that were also caught in He II 304 Å snapshots from STEREO/EUVI. The distinguishing features of blowout X-ray jets are (1) X-ray brightening inside the base arch in addition to the outside bright point that standard jets have, (2) blowout eruption of the base arch's core field, often carrying a filament of cool (T ~10 4-10 5 K) plasma, and (3) an extra jet-spire strand rooted close to the bright point. We present cartoons showing how reconnection during blowout eruption of the base arch could produce the observed features of blowout X-ray jets. We infer that (1) the standardjet/blowout-jet dichotomy of coronal jets results from the dichotomy of base arches that do not have and base arches that do have enough shear and twist to erupt open, and (2) there is a large class of spicules that are standard jets and a comparably large class of spicules that are blowout jets.

Formation of a rotating jet during the filament eruption on 2013 April 10–11

“…On the other hand, rapid changes in the flux distribution in the corona can be caused by instabilities of pre-existing coronal flux ropes. The presence of flux ropes in jet source regions and their eruption during jet formation is supposed in many blowout jet events (Filippov et al 2009;Moore et al 2010;Liu et al 2011;Shen et al 2011;Schmieder et al 2013) and used as a jet driver in many models (Archontis & Hood 2013;Lee et al 2015). However, observations of the pre-existing flux ropes (as filaments) are few (Shen et al 2012;Filippov et al 2013).…”

Observed Aspects of Reconnection in Solar Eruptions

“…If the eruption makes the ejected plasma hot enough to be seen in coronal X-ray movies such as from Yohkoh/SXT or from the Hinode X-Ray Telescope (XRT), the eruption is observed as an X-ray jet (Shibata et al 1992). If the ejected plasma is heated only to subcoronal temperatures, the ejection can't be seen in coronal X-ray images but can be seen in EUV images and/or in visible-wavelength chromospheric (e.g., Hα) images and is then called an EUV or chromospheric jet, surge, or macrospicule (Shibata 2001;Moore et al 2010).…”

“…An X-ray jet of this type, a blowout jet, amounts to a miniature embedded-arcade ejective eruption in which the eruptive arcade is embedded in high-reaching unipolar field. The eruption of the emerging sheared-core arcade appears to be unleashed partly by breakout reconnection at the current-sheet interface between the unipolar ambient field and the opposite-polarity leg of the impacted arcade, and partly by tether-cutting reconnection of the legs of the erupting arcade as in major flare/CME eruptions initiated by breakout reconnection (Patsourakos et al 2008;Pariat et al 2009;Rachmeler et al 2010;Moore et al 2010). In these X-ray jets, the hot "flare" loops made at the outside edge of the arcade by the breakout reconnection are typically much smaller than the erupting arcade, indicating that the breakout-reconnection current sheet is of similarly small extent (Moore et al 2010).…”

“…The eruption of the emerging sheared-core arcade appears to be unleashed partly by breakout reconnection at the current-sheet interface between the unipolar ambient field and the opposite-polarity leg of the impacted arcade, and partly by tether-cutting reconnection of the legs of the erupting arcade as in major flare/CME eruptions initiated by breakout reconnection (Patsourakos et al 2008;Pariat et al 2009;Rachmeler et al 2010;Moore et al 2010). In these X-ray jets, the hot "flare" loops made at the outside edge of the arcade by the breakout reconnection are typically much smaller than the erupting arcade, indicating that the breakout-reconnection current sheet is of similarly small extent (Moore et al 2010). So, most of the released free energy that drives a blowout jet probably comes from the sheared and twisted interior of the erupting arcade as in major CME eruptions initiated by breakout reconnection, rather than from the pre-eruption field sandwiching the current sheet at which the breakout reconnection sets in as the eruption starts.…”

Simulations of Solar Jets Confined by Coronal Loops

“…Cool surges and hot jets are sometimes observed together, in close association in space and time (Canfield et al 1996). Subsequent improvements in the spatial resolutions and temporal cadences of space-borne instruments have enabled more detailed studies of jets and surges from the Solar and Heliospheric Observatory (SOHO; e.g., Wang et al 1998), the Transition Region and Coronal Explorer (e.g., Chae et al 1999), the Solar-Terrestrial Relations Observatory (e.g., Patsourakos et al 2008), Hinode (e.g., Cirtain et al 2007;Savcheva et al 2007;Nishizuka et al 2008;Török et al 2009;Moore et al 2010Moore et al , 2013Liu et al 2011), the Solar Dynamics Observatory (SDO; e.g., Shen et al 2011;Guo et al 2013;Lee et al 2013;Schmieder et al 2013;Zheng et al 2013), and the Interface Region Imaging Spectrograph (e.g., Tian et al 2014;Cheung et al 2015).…”