Surge-like Oscillations above Sunspot Light Bridges Driven by Magnetoacoustic Shocks

Zhang, Jingwen; He, Jiansen; Wang, Linghua

doi:10.3847/1538-4357/aa63e8

Cited by 44 publications

(44 citation statements)

References 42 publications

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“…4 is caused by reconnection-related shock heating. Moreover, the intermittent and aperiodic occurrences of these jets also exclude the possible role of the p-mode wave on driving the jets, which is often suggested to account for the oscillating light walls above light bridges with a dominant period of several minutes (Yang et al 2015;Zhang et al 2017;Hou et al 2017;Tian et al 2018). One may see from the time-distance plots in Fig.…”

Section: Summary and Discussionmentioning

confidence: 88%

“…The most prominent feature of light walls is their coherent oscillating bright fronts in 1330/1400 Å channel, which have rising speeds of about 10-20 km s −1 (Yang et al 2015). Zhang et al (2017) found that the core of the IRIS Mg ii k 2796.35 Å line within an oscillating light wall above a light bridge repeatedly experiences a fast, impulsive blueward excursion followed by gradual motion to a redshift. The authors proposed that these oscillating walls result from upward shocked p-mode waves.…”

Section: Introductionmentioning

confidence: 92%

“…The structures mentioned above are usually derived from local inhomogeneous magnetic field and magneto-convection, indicating the complexity of sunspot magnetic and thermal properties (Spruit & Scharmer 2006;Schüssler & Vögler 2006;Rimmele 2008;Rempel et al 2009;Reardon et al 2013). As a result of the deviation from sunspot background conditions, various dynamic phenomena especially surge-like activities frequently occur around these structures, such as surges and light walls above the light bridges (Roy 1973;Asai et al 2001;Shimizu et al 2009;Louis et al 2014a;Yang et al 2015Yang et al , 2016Yang et al , 2017Bharti 2015;Robustini et al 2016;Hou et al 2016aHou et al ,b, 2017Zhang et al 2017;Tian et al 2018;Bai et al 2019), transient jets above a penumbral filament intrusion into the umbra (Bharti et al 2017), and ubiquitous penumbral microjets in the penumbral chromosphere (Katsukawa et al 2007b;Jurčák & Katsukawa 2008;Nakamura et al 2012;Tiwari et al 2016;Drews & Rouppe van der Voort 2017;Samanta et al 2017;Esteban Pozuelo et al 2019; Rouppe van der Voort & Drews 2019). These surge-like activities display an impressive variety of morphological, temporal, and spectral properties.…”

Section: Introductionmentioning

confidence: 99%

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Sunspot penumbral filaments intruding into a light bridge and the resultant reconnection jets

Hou

Zhong

et al. 2020

A&A

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Context. Penumbral filaments and light bridges are prominent structures inside sunspots and are important for understanding the nature of sunspot magnetic fields and magneto-convection underneath. Aims. We investigate an interesting event where several penumbral filaments intrude into a sunspot light bridge. In doing so we aim to gain further insight into the magnetic fields of the sunspot penumbral filament and light bridge, as well as their interaction. Methods. Combining data from the New Vacuum Solar Telescope, Solar Dynamics Observatory, and Interface Region Imaging Spectrograph, we study the emission, kinematic, and magnetic topology characteristics of the penumbral filaments intruding into the light bridge and the resultant jets. Results. At the west part of the light bridge, the intruding penumbral filaments penetrate into the umbrae on both sides of the light bridge, and two groups of jets are also detected. The jets share the same projected morphology with the intruding filaments and are accompanied by intermittent footpoint brightenings. Simultaneous spectral imaging observations provide convincing evidence for the presences of magnetic-reconnection-related heating and bidirectional flows near the jet bases and contribute to measuring the vector velocities of the jets. Additionally, nonlinear force-free field extrapolation results reveal strong and highly inclined magnetic fields along the intruding penumbral filaments, highly consistent with the results deduced from the vector velocities of the jets. Therefore, we propose that the jets could be caused by magnetic reconnections between emerging fields within the light bridge and the nearly horizontal fields of intruding filaments. The jets are then ejected outward along the stronger filament fields. Conclusions. Our study indicates that magnetic reconnection could occur between the penumbral filament fields and emerging fields within the light bridge and produce jets along the stronger filament fields. These results further complement the study of magnetic reconnection and dynamic activities within the sunspot.

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Section: Summary and Discussionmentioning

confidence: 88%

Section: Introductionmentioning

confidence: 92%

Section: Introductionmentioning

confidence: 99%

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Sunspot penumbral filaments intruding into a light bridge and the resultant reconnection jets

Hou

Zhong

et al. 2020

A&A

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“…Figure 3 shows an example of the surge and the bright front ahead of the surge. Zhang et al (2017) analyzed the kinematics of such a bright front in another light bridge observation by IRIS, and found parabolic trajectories of the bright front. They also found a linear correlation between the maximum velocity and deceleration of the motion of the bright front, suggesting the nature of these long-lasting oscillatory motions to be slow-mode shock waves.…”

Section: Dynamics In the Tr Above Sunspotsmentioning

confidence: 99%

The transition region above sunspots

Samanta

Zhang

2018

Geosci. Lett.

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Over decades, sunspots and their fine structures have been studied in detail at the photospheric level with different ground-based telescopes, as the surface of the Sun primarily emits light in the visible wavelengths. For a very long period, the upper atmosphere above the sunspot regions, especially the transition region (TR) above sunspots where the plasma emits light in the far ultraviolet (FUV) and extreme ultraviolet (EUV), has been poorly understood. In the past decades after the development of space instrumentations, FUV and EUV observations have uncovered many secrets of the TR above sunspots. In this paper, we present a brief review of research results about the TR structures and dynamics obtained through imaging and spectroscopic observations of sunspots in the past ~ 20 years. Though these observations have gathered remarkable and detailed information and greatly improved our understanding of the TR above the sunspots, paradoxically, they leave us with many new questions which should be answered in the future.

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“…Another sunspot element where asymmetry of the plasma environment could heavily influence wave propagation is the light bridge and corresponding light wall reaching up into higher layers of the atmosphere, which are trapped between two, sometimes vastly different umbral cores. Oscillations recently detected in light walls have been interpreted as signatures of propagating magneto-acoustic (shock) waves (Yang et al, 2015;Zhang et al, 2017).…”

Section: Discussionmentioning

confidence: 99%

Magnetohydrodynamic Waves in Multi-Layered Asymmetric Waveguides: Solar Magneto-Seismology Theory and Application

Allcock

Shukhobodskaia

Zsámberger

et al. 2019

Front. Astron. Space Sci.

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Diagnosing the solar atmospheric plasma is one of the major challenges in solar physics. Magnetohydrodynamic (MHD) waves, by means of applying the powerful concept of solar magneto-seismology (SMS), provide a tool to obtain diagnostic insight into the magnetized solar plasma in MHD waveguides. This paper provides a road-map of simple but applicable models of solar atmospheric waveguides in the framework of Cartesian geometry. We focus on exploiting the diagnostic potential of waveguide asymmetry and consider the effects of steady flow. In particular, the dispersion relation describing linear MHD wave propagation along a multi-layered MHD waveguide is derived. Aiming at lower solar atmospheric applications of SMS, the special case of a single magnetic slab embedded in an asymmetric magnetized plasma environment is revisited. As a proof of concept, the Amplitude Ratio Method is used to make a seismological estimate of the local Alfvén speed in several chromospheric fibrils that exhibit asymmetric oscillations. Absolute ratios of boundary oscillations between 1.29 and 3.42 are detected and, despite the significant errors expected, the local Alfvén speed estimates agree with previously derived estimates from magnetic field extrapolations. Finally, the effects of asymmetric shear flows present in these slab MHD waveguides are considered as a suitable model of Kelvin-Helmholtz instability initiation that is applicable, for example, to coronal mass ejection flanks.

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Surge-like Oscillations above Sunspot Light Bridges Driven by Magnetoacoustic Shocks

Cited by 44 publications

References 42 publications

Sunspot penumbral filaments intruding into a light bridge and the resultant reconnection jets

Sunspot penumbral filaments intruding into a light bridge and the resultant reconnection jets

The transition region above sunspots

Magnetohydrodynamic Waves in Multi-Layered Asymmetric Waveguides: Solar Magneto-Seismology Theory and Application

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