Small-scale solar jet formation and their associated waves and instabilities

Skirvin, Samuel; Verth, G.; González-Avilés, J. J.; Shelyag, Sergiy; Sharma, Rahul; Guzmán, F. S.; Ballai, I.; Scullion, Eamon; Silva, Suzana S.A.; Fedun, V.

doi:10.1016/j.asr.2022.05.033

Cited by 8 publications

(3 citation statements)

References 206 publications

(230 reference statements)

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“…Any typical location on the solar surface is oscillating with an amplitude of a few hundred meters per second (Ulrich 1970) which results in about 10 cm s −1 per individual mode (Priest 2014). Solar p-modes have been shown to leak power into the lower atmosphere, which may be important to explain some observed dynamics through driving jet phenomena (De Pontieu et al 2004;Hansteen et al 2006;Heggland et al 2007;Skirvin et al 2023) and may be used as a tool for seismology of the local plasma (Chaplin & Basu 2008).…”

Section: Introductionmentioning

confidence: 99%

Alfvénic Motions Arising from Asymmetric Acoustic Wave Drivers in Solar Magnetic Structures

Skirvin¹,

Gao

Doorsselaere³

2023

ApJ

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Alfvénic motions are ubiquitous in the solar atmosphere and their observed properties are closely linked to those of photospheric p-modes. However, it is still unclear how a predominantly acoustic wave driver can produce these transverse oscillations in the magnetically dominated solar corona. In this study we conduct a 3D magnetohydrodynamic numerical simulation to model a straight, expanding coronal loop in a gravitationally stratified solar atmosphere which includes a transition region and chromosphere. We implement a driver locally at one foot-point corresponding to an acoustic–gravity wave which is inclined by θ = 15° with respect to the vertical axis of the magnetic structure and is equivalent to a vertical driver incident on an inclined loop. We show that transverse motions are produced in the magnetic loop, which displace the axis of the waveguide due to the breaking of azimuthal symmetry, and study the resulting modes in the theoretical framework of a magnetic cylinder model. By conducting an azimuthal Fourier analysis of the perturbed velocity signals, the contribution from different cylindrical modes is obtained. Furthermore, the perturbed vorticity is computed to demonstrate how the transverse motions manifest themselves throughout the whole non-uniform space. Finally we present some physical properties of the Alfvénic perturbations and present transverse motions with velocity amplitudes in the range 0.2–0.75 km s−1 which exhibit two distinct oscillation regimes corresponding to 42 and 364 s, where the latter value is close to the period of the p-mode driver in the simulation.

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Section: Introductionmentioning

confidence: 99%

Alfvénic Motions Arising from Asymmetric Acoustic Wave Drivers in Solar Magnetic Structures

Skirvin¹,

Gao

Doorsselaere³

2023

ApJ

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“…Sunspot or pore can be of interest for DI. But the more smaller radial size, the stronger the DI, so in our view, the detection of DI may be more available for small scale jets (Kotani & Shibata 2020;Muglach 2021;Skirvin et al 2023) or small magnetic loops (Martínez González & Bellot Rubio 2009;Gömöry et al 2010).…”

Section: Discussionmentioning

confidence: 97%

Dissipative Instability of Magnetohydrodynamic Sausage Waves in a Compressional Cylindrical Plasma: Effect of Flow Shear and Viscosity Shear

Yu 유

2023

ApJ

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The shear flow influences the stability of magnetohydrodynamic (MHD) waves. In the presence of a dissipation mechanism, flow shear may induce an MHD wave instability below the threshold of the Kelvin–Helmholtz instability, which is called dissipative instability. This phenomenon is also called negative energy wave instability because it is closely related to the backward wave, which has negative wave energy. Considering viscosity as a dissipation mechanism, we derive an analytical dispersion relation for the slow sausage modes in a straight cylinder with a discontinuous boundary. It is assumed that the steady flow is inside and dynamic and bulk viscosities are outside the circular flux tube under photospheric condition. When the two viscosities are weak, it is found that for the slow surface mode, the growth rate is proportional to the axial wavenumber and flow shear, consistent within the incompressible limit. For a slow body mode, the growth rate has a peak at a certain axial wavenumber, and its order of magnitude is similar to surface mode. The linear relationship between the growth rate and the dynamic viscosity established in the incompressible limit develops nonlinearly when the flow shear and/or the two viscosities are sufficiently strong.

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“…In the solar atmosphere, vortical plasma motions are an important part of its dynamics. They may be responsible for magnetohydrodynamic (MHD) wave excitation (Schuessler 1984;Attie et al 2009;Fedun et al 2011;Kitiashvili et al 2011;Yadav et al 2022) and the formation of plasma jets (Kitiashvili et al 2013;Iijima & Yokoyama 2017;Snow et al 2018;Skirvin et al 2023) and act as a channel for energy transfer to the solar corona (Shelyag et al 2012;Wedemeyer-Böhm et al 2012;Yadav et al 2021). To understand the mechanism of vortex formation and its role in the plasma processes mentioned above, the precise automated identification of a vortex structure is essential (Tziotziou et al 2023).…”

Section: Introductionmentioning

confidence: 99%

Advanced Γ Method for Small-scale Vortex Detection in the Solar Atmosphere

Yuan,

de Souza e Almeida Silva,

Fedun

et al. 2023

ApJS

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Ubiquitous vortical structures are considered to act as a natural source of various solar plasma phenomena, for example, a wide range of magnetohydrodynamic waves and jet excitations. This work aims to develop an advanced vortex detection algorithm based on the Γ method and using a separable convolution kernel technique. This method is applied to detect and analyze the photospheric vortices in 3D realistic magnetoconvection numerical and observational data. We present the advanced Γ method (AGM), and our results indicate that the AGM performs with better accuracy in comparison with the original Γ method. The AGM allows us to identify small- and large-scale vortices with no vortex interposition and without requiring the changing of the threshold. In this way, the nondetection issue is mostly prevented. It was found that the Γ method failed to identify the large and longer-lived vortices, which were detected by the AGM. The size of the detected vortical structures tends to vary over time, with most vortices shrinking toward their end. The vorticity at the center is also not constant, presenting a sharp decay as the vortex ceases to exist. Due to its capability of identifying vortices with minimum nondetection, the vortex properties—such as lifetime, geometry, and dynamics—are better captured by the AGM than by the Γ method. In this era of new high-resolution observation, the AGM can be used as a precise technique for identifying and performing statistical analysis of solar atmospheric vortices.

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Small-scale solar jet formation and their associated waves and instabilities

Cited by 8 publications

References 206 publications

Alfvénic Motions Arising from Asymmetric Acoustic Wave Drivers in Solar Magnetic Structures

Alfvénic Motions Arising from Asymmetric Acoustic Wave Drivers in Solar Magnetic Structures

Dissipative Instability of Magnetohydrodynamic Sausage Waves in a Compressional Cylindrical Plasma: Effect of Flow Shear and Viscosity Shear

Advanced Γ Method for Small-scale Vortex Detection in the Solar Atmosphere

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