Blobs in recurring extreme-ultraviolet jets

Zhang, Q. M.; Ji, Haisheng

doi:10.1051/0004-6361/201423698

Cited by 85 publications

(91 citation statements)

References 87 publications

(105 reference statements)

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The plasmoids or blob-like structures are also reported in the spire during the evolution of the coronal jets as seen in observations and models (e.g., Zhang and Ji, 2014;Zhang, Ji and Su, 2016;Zhang and Zhang, 2017;Ni et al, 2017). These localized plasma blobs are formed at the junction of the jet-plasma spire and the base-arch field.…”

Section: Introductionmentioning

confidence: 67%

CME Productive and Non-productive Recurring Jets Near an Active Region AR11176

2020

View full text Add to dashboard Cite

We study the recurring jets near AR11176 during the period 2011 March 31 17:00 UT to April 1 05:00 UT using observations from the Atmospheric Imaging Assembly (AIA) on board Solar Dynamics Observatory (SDO). Minifilaments (mini-filament1 & 2) are found at the base of these recurring jets where mini-filament1 shows the partial signature of eruption in case of Jet1-3. However, the mini-filament2 shows a complete eruption driving a full blow-out jet (Jet4). The eruption of mini-filament2 triggers C-class flare and Jet4 eruption. The eruption of Jet4 triggers a coronal mass ejection (CME). The plane-of-sky velocity of recurring jets (Jet1-4) results in 160 km s −1 , 106 km s −1 , 151 km s −1 and 369 km s −1 . The estimated velocity of CME is 636 km s −1 . The continuous magnetic flux cancellation is observed at the base of the jet productive region which could be the cause of the eruption of mini-filaments and recurring jets. In the former case, the mini-filament1 shows partial eruption and first three jets (Jet1-3) are produced, but the rate of cancellation was rather low. However, in the latter case, mini-filament2 fully erupts (perhaps because of a higher cancellation rate), and this triggers a C-class flare and a CME-productive jet. At the base of first three jets (Jet1-3), the mini-filament1 causes to push the overlying dynamic complex thin loops resulting in the reconnection and drives the jet (Jet1-3) eruptions. The formation of the plasma blobs are observed during the eruption of the first jet (Jet1).

show abstract

Section: Introductionmentioning

confidence: 67%

CME Productive and Non-productive Recurring Jets Near an Active Region AR11176

2020

View full text Add to dashboard Cite

show abstract

“…Once the flux ropes were ejected, new ones formed in their place, and the process was repeated as the jet proceeded. This repeated formation and ejection of plasma blobs provides a natural explanation for the intermittent outflows, bright blobs of emission, and quasiperiodic intensity fluctuations observed in some jets (e.g., Singh et al 2011Singh et al , 2012Morton et al 2012;Zhang & Ji 2014;Filippov et al 2015). The thread-like nature of the tearingmediated outflows may also explain the filamentary structure often observed in jets (e.g., Singh et al 2011;Cheung et al 2015).…”

Section: Discussionmentioning

confidence: 91%

“…Recent Interface Region Imaging Spectrograph (IRIS) observations of an active-region jet revealed filamentary fine-scale structure in the emission from the reconnection region (Cheung et al 2015). Solar Dynamics Observatory observations have shown blobs forming in both small (Zhang & Ji 2014) and large (Filippov et al 2015) open-field EUV jets. Recent Solar TErrestrial RElations Observatory observations have also revealed trains of plasma blobs within jets in the closed-field corona near active regions (Zhang et al 2016).…”

Section: Introductionmentioning

confidence: 99%

Three-Dimensional Simulations of Tearing and Intermittency in Coronal Jets

Wyper

DeVore

Karpen

et al. 2016

ApJ

View full text Add to dashboard Cite

Observations of coronal jets increasingly suggest that local fragmentation and intermittency play an important role in the dynamics of these events. In this work, we investigate this fragmentation in high-resolution simulations of jets in the closed-field corona. We study two realizations of the embedded-bipole model, whereby impulsive helical outflows are driven by reconnection between twisted and untwisted field across the domed fan plane of a magnetic null. We find that the reconnection region fragments following the onset of a tearing-like instability, producing multiple magnetic null points and flux-rope structures within the current layer. The flux ropes formed within the weak-field region in the center of the current layer are associated with "blobs" of density enhancement that become filamentary threads as the flux ropes are ejected from the layer, whereupon new flux ropes form behind them. This repeated formation and ejection of flux ropes provides a natural explanation for the intermittent outflows, bright blobs of emission, and filamentary structure observed in some jets. Additional observational signatures of this process are discussed. Essentially all jet models invoke reconnection between regions of locally closed and locally open field as the jet-generation mechanism. Therefore, we suggest that this repeated tearing process should occur at the separatrix surface between the two flux systems in all jets. A schematic picture of tearing-mediated jet reconnection in three dimensions is outlined.

show abstract

“…Also, Chen et al (2013) studied the temperature structure of an AR jet using the same DEM method and find hot plasma ∼7 MK at the footpoint of jet. Zhang & Ji (2014) investigate the temperature of plasma blobs that were observed along the spire of a recurrent AR jet using the DEM method, "xrt_dem_iterative2.pro", along with Monte Carlo (MC) simulations (details in Cheng et al 2012). The authors find the DEM-weighted average temperatures of the three blobs to range from 0.5 to 4 MK with a median value of ∼2.3 MK, and the densities of 3.3, 1.9, and 2.1 × 10 9 cm −3 , respectively.…”

Section: Introductionmentioning

confidence: 99%

Multiwavelength study of 20 jets that emanate from the periphery of active regions

Mulay

Tripathi

Zanna

et al. 2016

A&A

View full text Add to dashboard Cite

Aims. We present a multiwavelength analysis of 20 EUV jets which occurred at the periphery of active regions close to sunspots. We discuss the physical parameters of the jets and their relation with other phenomena such as Hα surges, nonthermal type-III radio bursts and hard X-ray (HXR) emission. Methods. These jets were observed between August 2010 and June 2013 by the Atmospheric Imaging Assembly (AIA) instrument that is onboard the Solar Dynamic Observatory (SDO). We selected events that were observed on the solar disk within +/-60• latitude. Using AIA wavelength channels that are sensitive to coronal temperatures, we studied the temperature distribution in the jets using the line of sight (LOS) differential emission measure (DEM) technique. We also investigated the role of the photospheric magnetic field using the LOS magnetogram data from the Helioseismic and Magnetic Imager (HMI) onboard SDO. Results. It has been observed that most of the jets originated from the western periphery of active regions. Their lifetimes range from 5 to 39 min with an average of 18 min and their velocities range from 87 to 532 km s −1 with an average of 271 km s −1 . All the jets are co-temporally associated with Hα surges. Most of the jets are co-temporal with nonthermal type-III radio bursts observed by the Wind/WAVES spacecraft in the frequency range from 20 kHz to 13 MHz. We confirm the source region of these bursts using the potential field source surface (PFSS) technique. Using Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) observations, we found that half of the jets produced HXR emission and they often shared the same source region as the HXR emission (6−12 keV). Ten out of 20 events showed that the jets originated in a region of flux cancellation and six jets in a region of flux emergence. Four events showed flux emergence and then cancellation during the jet evolution. DEM analyses showed that for most of the spires of the jets, the DEM peaked at around log T [K] = 6.2/6.3 (∼2 MK). In addition, we derived an emission measure and a lower limit of electron density at the location of the spire (jet 1: log EM = 28.6, N e = 1.3 × 10 10 cm −3 ; jet 2: log EM = 28.0, N e = 8.6 × 10 9 cm −3 ) and the footpoint (jet 1 -log EM = 28.6, N e = 1.1 × 10 10 cm −3 ; jet 2: log EM = 28.1, N e = 8.4 × 10 9 cm −3 ). These results are in agreement with those obtained earlier by studying individual active region jets. Conclusions. The observation of flux cancellation, the association with HXR emission and emission of nonthermal type-III radio bursts, suggest that the initiation and therefore, heating is taking place at the base of the jet. This is also supported by the high temperature plasma revealed by the DEM analysis in the jet footpoint (peak in the DEM at log T [K] = 6.5). Our results provide substantial constraints for theoretical modeling of the jets and their thermodynamic nature.

show abstract

Blobs in recurring extreme-ultraviolet jets

Cited by 85 publications

References 87 publications

CME Productive and Non-productive Recurring Jets Near an Active Region AR11176

CME Productive and Non-productive Recurring Jets Near an Active Region AR11176

Three-Dimensional Simulations of Tearing and Intermittency in Coronal Jets

Multiwavelength study of 20 jets that emanate from the periphery of active regions

Contact Info

Product

Resources

About