Evidence for Precursors of the Coronal Hole Jets in Solar Bright Points

Bagashvili, S. R.; Shergelashvili, B. M.; Japaridze, D. R.; Kukhianidze, V.; Poedts, Stefaan; Zaqarashvili, T. V.; Khodachenko, M. L.; Causmaecker, Patrick De

doi:10.3847/2041-8213/aab08b

Cited by 13 publications

(20 citation statements)

References 44 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The global wavelet spectrum in panel b shows the distribution of power spectra over time. Bagashvili et al (2018) investigated the intensity at the base of several jets issued from a coronal hole and obtained similar results concerning the periodicity and duration of the oscillations.…”

Section: Oscillations Before the Jet Activitymentioning

confidence: 79%

“…A first significant finding is the observation of pre-jet activity, in particular in the form of oscillatory behaviour. The pre-jet activity of quiet-region jets observed in the hot AIA filters has been studied previously (Bagashvili et al 2018). The jets originated in coronal bright points, and the bright points showed oscillatory behaviour before the onset of jet activity.…”

Section: Discussionmentioning

confidence: 95%

“…The observational analysis from previous studies has revealed that the jet evolution might be preceded by some wavelike or oscillatory disturbances (Pucci et al 2012;Li et al 2015;Bagashvili et al 2018). Pucci et al (2012) analysed the X-ray jets observed by Hinode November 2−4, 2007 and found that most of the jets are associated with oscillations of the coronal emission in bright points (for a recent review of coronal bright points, see Madjarska 2019) at the base of the jets.…”

Section: Introductionmentioning

confidence: 99%

“…They concluded that the pre-jet oscillations are the result of the change in area or temperature of the pre-jet activity region. Recently, a statistical analysis of pre-jet oscillations of coronal hole jets has been carried out by Bagashvili et al (2018). They reported that 20 out of 23 jets in their study were preceded by pre-jet intensity oscillations some 12−15 min before the onset of the jet.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Case study of multi-temperature coronal jets for emerging flux MHD models

Joshi

Chandra

Schmieder

et al. 2020

A&A

View full text Add to dashboard Cite

Context. Hot coronal jets are a basic observed feature of the solar atmosphere whose physical origin is still actively debated. Aims. We study six recurrent jets that occurred in active region NOAA 12644 on April 4, 2017. They are observed in all the hot filters of AIA as well as cool surges in IRIS slit–jaw high spatial and temporal resolution images. Methods. The AIA filters allow us to study the temperature and the emission measure of the jets using the filter ratio method. We studied the pre-jet phases by analysing the intensity oscillations at the base of the jets with the wavelet technique. Results. A fine co-alignment of the AIA and IRIS data shows that the jets are initiated at the top of a canopy-like double-chambered structure with cool emission on one and hot emission on the other side. The hot jets are collimated in the hot temperature filters, have high velocities (around 250 km s−1) and are accompanied by cool surges and ejected kernels that both move at about 45 km s−1. In the pre-phase of the jets, we find quasi-periodic intensity oscillations at their base that are in phase with small ejections; they have a period of between 2 and 6 min, and are reminiscent of acoustic or magnetohydrodynamic waves. Conclusions. This series of jets and surges provides a good case study for testing the 2D and 3D magnetohydrodynamic emerging flux models. The double-chambered structure that is found in the observations corresponds to the regions with cold and hot loops that are in the models below the current sheet that contains the reconnection site. The cool surge with kernels is comparable with the cool ejection and plasmoids that naturally appears in the models.

show abstract

Section: Oscillations Before the Jet Activitymentioning

confidence: 79%

Section: Discussionmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Case study of multi-temperature coronal jets for emerging flux MHD models

Joshi

Chandra

Schmieder

et al. 2020

A&A

View full text Add to dashboard Cite

show abstract

“…The observation of reconnection jets 21,24 provided motivation for carrying out the experimental setup of the present study to shed light on a possible mechanism for the creation of solar jets. The main actor in this regard is the Alfvén wave where the domain under consideration is a magnetic reconnection site 25 .…”

mentioning

confidence: 99%

How Alfvén waves induce compressive flows in the neighborhood of a 2.5D magnetic null-point

Sabri

Farahani

Ebadi

et al. 2020

Sci Rep

View full text Add to dashboard Cite

The aim of the present study is to provide insight on the induced compressive perturbations together with the modifications of the environmental parameters in the course of Alfvén wave interaction with a solar magnetic null-point. The shock-capturing Godunov-type code PLUTO is used to solve the set of ideal magnetohydrodynamic equations. The nonlinear effects connected with an initial Alfvén pulse nearing a magnetic null point induces fast and slow magnetoacoustic waves with anti phase conduct. The induced current density and flows are independent of the local plasma-$$\beta$$ β at the reconnection site. The induced inflows and outflows highly depend on the polarization. The inflows have a stronger effect compared to the outflows in both the x and y directions showing its peak in the x-direction. The dominant wave that couples to flows is the fast wave due to the in-phase harmony between perturbations of the compressive parameters and the fast wave. The induced current density possesses a steady orientation at the reconnection site which governs the diffusion or propagation of the waves. Induced perturbations by the nonlinear forces together with their back reaction on the Alfvén wave have a significant role in the current density excitation being responsible for the creation of inflows and outflows that are possible candidates for the creation of solar jets which has a significant contribution towards coronal seismology.

show abstract

Case study on the identification and classification of small-scale flow patterns in flaring active region

Philishvili

Shergelashvili

Buitendag

et al. 2021

A&A

Self Cite

View full text Add to dashboard Cite

Context. We propose a novel methodology to identity flows in the solar atmosphere and classify their velocities as either supersonic, subsonic, or sonic. Aims. The proposed methodology consists of three parts. First, an algorithm is applied to the Solar Dynamics Observatory (SDO) image data to locate and track flows, resulting in the trajectory of each flow over time. Thereafter, the differential emission measure inversion method is applied to six Atmospheric Imaging Assembly (AIA) channels along the trajectory of each flow in order to estimate its background temperature and sound speed. Finally, we classify each flow as supersonic, subsonic, or sonic by performing simultaneous hypothesis tests on whether the velocity bounds of the flow are larger, smaller, or equal to the background sound speed. Methods. The proposed methodology was applied to the SDO image data from the 171Å spectral line for the date 6 March 2012 from 12:22:00 to 12:35:00 and again for the date 9 March 2012 from 03:00:00 to 03:24:00. Eighteen plasma flows were detected, 11 of which were classified as supersonic, 3 as subsonic, and 3 as sonic at a 70% level of significance. Out of all these cases, 2 flows cannot be strictly ascribed to one of the respective categories as they change from the subsonic state to supersonic and vice versa. We labeled them as a subclass of transonic flows. Results. The proposed methodology provides an automatic and scalable solution to identify small-scale flows and to classify their velocities as either supersonic, subsonic, or sonic. It can be used to characterize the physical properties of the solar atmosphere. Conclusions. We identified and classified small-scale flow patterns in flaring loops. The results show that the flows can be classified into four classes: sub-, super-, trans-sonic, and sonic. The flows occur in the complex structure of the active region magnetic loops. The detected flows from AIA images can be analyzed in combination with the other high-resolution observational data, such as Hi-C 2.1 data, and be used for the development of theories describing the physical conditions responsible for the formation of flow patterns.

show abstract

Evidence for Precursors of the Coronal Hole Jets in Solar Bright Points

Cited by 13 publications

References 44 publications

Case study of multi-temperature coronal jets for emerging flux MHD models

Case study of multi-temperature coronal jets for emerging flux MHD models

How Alfvén waves induce compressive flows in the neighborhood of a 2.5D magnetic null-point

Case study on the identification and classification of small-scale flow patterns in flaring active region

Contact Info

Product

Resources

About