Macrospicules and Their Connection to Magnetic Reconnection in the Lower Solar Atmosphere

Abstract

Solar macrospicules are beam-like cool plasma ejections of size in between spicules and coronal jets, which can elucidate potential connections between plasma jetting activity at different scales. With high-resolution observations from the New Vacuum Solar Telescope and Solar Dynamics Observatory, we investigate the origin of five groups of recurrent active-region macrospicules. Before the launch of each macrospicule, we detect a compact bright patch (BP) at its base where a newly emerging dipole contacts and cancel with the preexisting ambient field. The spectral diagnosis from the Interface Region Imaging Spectrograph at one of BPs reveals signatures of reconnection at the lower atmosphere. Multiwavelength imaging of these BPs show that they mainly occur at the rising phase of the flux emergence and slowly ascend from the lower to the upper chromosphere. Remarkable macrospicules occur and fade out once the BPs appear and decay from the AIA 304 Å images, respectively. We suggest that these macrospicules and related BPs form in a common reconnection process, in which the increasing reconnection height between the emerging dipole and the ambient field results in the observed variations from BPs to macrospicules. Interestingly, most macrospicules show similar characteristics to larger-scale coronal jets and/or smaller-scale spicules, i.e., the rotating motions, the presence of minifilaments and BPs before the eruptions, and magnetic flux emergence and cancellation. We conclude that the formation mechanism of macrospicules should be the same as spicules and coronal jets, i.e., solar jetting phenomena at different scales share the same physical mechanism in association with magnetic reconnection.

Formation of Fan-spine Magnetic Topology through Flux Emergence and Subsequent Jet Production

“…These observational results align with the simulations carried out by Pariat et al (2015Pariat et al ( , 2016, which demonstrate that the genuine generation of coronal jets (with significant untwisting motion) only occur when a sufficient amount of energy is built up. Similarly, the variation in reconnection intensity from slow to explosive has also been found during the occurrence of macrospicules (Duan et al 2023). Finally, there appears to be no significant plasma ejection after the end of the three homologous jet eruptions.…”

“…The null point within the fan-spine magnetic topology system provides a highly favorable site for the occurrence of magnetic reconnection (e.g., Pontin et al 2011). In addition, many coronal mass ejections (CMEs) (Kumar et al 2021), white-light flares (Song & Tian 2018;Song et al 2018), small-scale coronal bright points (Zhang et al 2012), ultraviolet bursts (Chitta et al 2017;Chen et al 2019), as well as macrospicules (Duan et al 2023) are also suggested to occur in the fan-spine magnetic field configuration. Observationally, within the framework of fanspine structure, the occurrence of a solar eruption often manifests as three flare ribbons.…”

Alfvén pulse driven spicule-like jets in the presence of thermal conduction and ion-neutral collision in two-fluid regime

“…They are known as macrospicules. They [27][28][29][30][31]. These comparatively larger spicules may be observed in the polar region of the coronal holes.…”

“…They have impulsive origin and attain a maximum height of 7–70 Mm. Their typical lifetime is about 3–15 min, and vertical flow rate is ≈10--150 normalkm normals−1 [27–31]. These comparatively larger spicules may be observed in the polar region of the coronal holes.…”

Double-decker Pair of Flux Ropes Formed by Two Successive Tether-cutting Eruptions

“…The size of the filaments has a wide distribution from about 10 3 to 10 6 km (Liu 2020). While minifilament eruptions are capable of forming small-scale solar jets at anywhere in the lower solar atmosphere (e.g., Shen et al 2012aShen et al , 2017Sterling et al 2015;Hong et al 2016Hong et al , 2017Shen 2021;Duan et al 2023;Yang et al 2020Yang et al , 2023a, large-scale filament eruptions are the primary solar source for generating large-scale interplanetary magnetic storms that affect the near-Earth space environment (Chen 2011;Shen et al 2011bShen et al , 2012bBi et al 2013Bi et al , 2015Wang et al 2017b;Cliver et al 2022;Yang et al 2023b). How a filament maintains its equilibrium and stability in the corona is a key but unsolved question in filament physics.…”