Rapid Evolution of Type II Spicules Observed in Goode Solar Telescope On-disk H<sub>α</sub> Images

Yurchyshyn, Vasyl; Cao, Wenda; Abramenko, V. I.; Yang, Xu; Cho, Kyung-Suk

doi:10.3847/2041-8213/ab7931

Cited by 12 publications

(10 citation statements)

References 51 publications

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“…Alongside QPPs, oscillatory reconnection can also be associated with quasi-periodic flows associated with spicules (e.g., De Pontieu & McIntosh 2010;De Pontieu et al 2011;Samanta et al 2019;Yurchyshyn et al 2020), as well as with observed periodicities in jets (Hong et al 2019) and in the formation, disappearance, and eruption of magnetic flux ropes (Shen et al 2018;Xue et al 2019). McLaughlin et al (2012b) were able to reproduce such observed periodicities through oscillatory reconnection in a 2D flux emergence model.…”

Section: Introductionmentioning

confidence: 71%

The Independence of Oscillatory Reconnection Periodicity from the Initial Pulse

Karampelas

McLaughlin²,

Botha³

et al. 2022

ApJ

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Oscillatory reconnection can manifest through the interaction between the ubiquitous MHD waves and omnipresent null points in the solar atmosphere and is characterized by an inherent periodicity. In the current study, we focus on the relationship between the period of oscillatory reconnection and the strength of the wave pulse initially perturbing the null point, in a hot coronal plasma. We use the PLUTO code to solve the fully compressive, resistive MHD equations for a 2D magnetic X-point. Using wave pulses with a wide range of amplitudes, we perform a parameter study to obtain values for the period, considering the presence and absence of anisotropic thermal conduction separately. In both cases, we find that the resulting period is independent of the strength of the initial perturbation. The addition of anisotropic thermal conduction only leads to an increase in the mean value for the period, in agreement with our previous study. We also consider a different type of initial driver and we obtain an oscillation period matching the independent trend previously mentioned. Thus, we report for the first time on the independence between the type and strength of the initializing wave pulse and the resulting period of oscillatory reconnection in a hot coronal plasma. This makes oscillatory reconnection a promising mechanism to be used within the context of coronal seismology.

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Section: Introductionmentioning

confidence: 71%

The Independence of Oscillatory Reconnection Periodicity from the Initial Pulse

Karampelas

McLaughlin²,

Botha³

et al. 2022

ApJ

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“…Another important feature commonly observed in spicules is the rapid morphological transformations that they undergo both in space and time, including multiple splitting and branching (Yurchyshyn et al 2020). We refer to the examples shown in Fig.…”

Section: Spatial Distribution Of Spicules and Their Substructuresmentioning

confidence: 99%

Spicules and downflows in the solar chromosphere

Bose

Joshi

Henriques

et al. 2021

A&A

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Context. High-speed downflows have been observed in the solar transition region (TR) and lower corona for many decades. Despite their abundance, it has been hard to find signatures of such downflows in the solar chromosphere. Aims. In this work, we target an enhanced network region which shows ample occurrences of rapid spicular downflows in the Hα spectral line, which could potentially be linked to high-speed TR downflowing counterparts. Methods. We used the k-means algorithm to classify the spectral profiles of on-disk spicules in Hα and Ca II K data observed from the Swedish 1 m Solar Telescope and employed an automated detection method based on advanced morphological image processing operations to detect such downflowing features, in conjunction with rapid blue-shifted and red-shifted excursions (RBEs and RREs). Results. We report the existence of a new category of RREs (termed as downflowing RRE) for the first time that, contrary to earlier interpretation, are associated with chromospheric field aligned downflows moving toward the strong magnetic field regions. Statistical analysis performed on nearly 20 000 RBEs and 15 000 RREs (including the downflowing counterparts), which were detected in our 97 min long dataset, shows that the downflowing RREs are very similar to RBEs and RREs except for their oppositely directed plane-of-sky motion. Furthermore, we also find that RBEs, RREs, and downflowing RREs can be represented by a wide range of spectral profiles with varying Doppler offsets, and Hα line core widths, both along and perpendicular to the spicule axis, that causes them to be associated with multiple substructures which evolve together. Conclusions. We speculate that these rapid plasma downflows could well be the chromospheric counterparts of the commonly observed TR downflows.

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“…Oscillatory reconnection is also a possible mechanism behind phenomena like periodicities observed in jets (Hong et al 2019), periodic behavior associated with the formation, disappearance, and eruption of magnetic flux ropes (Shen et al 2018;Xue et al 2019) and quasiperiodic flows associated with spicules in the solar atmosphere (e.g. De Pontieu & McIntosh 2010;De Pontieu et al 2011;Samanta et al 2019;Yurchyshyn et al 2020). For spicules, a 2D flux emergence model that triggered the oscillatory reconnection mechanism was able to reproduce such flows with the observed periodicities (McLaughlin et al 2012b).…”

Section: Introductionmentioning

confidence: 94%

Oscillatory Reconnection of a 2D X-point in a hot coronal plasma

Karampelas,

McLaughlin,

Botha

et al. 2021

Preprint

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Oscillatory reconnection (a relaxation mechanism with periodic changes in connectivity) has been proposed as a potential physical mechanism underpinning several periodic phenomena in the solar atmosphere including, but not limited to, quasi-periodic pulsations (QPPs). Despite its importance, however, the mechanism has never been studied within a hot, coronal plasma. We investigate oscillatory reconnection in a one million Kelvin plasma by solving the fully-compressive, resistive MHD equations for a 2D magnetic X-point under coronal conditions using the PLUTO code. We report on the resulting oscillatory reconnection including its periodicity and decay rate. We observe a more complicated oscillating profile for the current density compared to that found for a cold plasma, due to modeconversion at the equipartition layer. We also consider, for the first time, the effect of adding anisotropic thermal conduction to the oscillatory reconnection mechanism, and we find this simplifies the spectrum of the oscillation profile and increases the decay rate. Crucially, the addition of thermal conduction does not prevent the oscillatory reconnection mechanism from manifesting. Finally, we reveal a relationship between the equilibrium magnetic field strength, decay rate, and period of oscillatory reconnection, which opens the tantalising possibility of utilizing oscillatory reconnection as a seismological tool.

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Rapid Evolution of Type II Spicules Observed in Goode Solar Telescope On-disk H_α Images

Cited by 12 publications

References 51 publications

The Independence of Oscillatory Reconnection Periodicity from the Initial Pulse

The Independence of Oscillatory Reconnection Periodicity from the Initial Pulse

Spicules and downflows in the solar chromosphere

Oscillatory Reconnection of a 2D X-point in a hot coronal plasma

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Rapid Evolution of Type II Spicules Observed in Goode Solar Telescope On-disk Hα Images

Cited by 12 publications

References 51 publications

The Independence of Oscillatory Reconnection Periodicity from the Initial Pulse

The Independence of Oscillatory Reconnection Periodicity from the Initial Pulse

Spicules and downflows in the solar chromosphere

Oscillatory Reconnection of a 2D X-point in a hot coronal plasma

Contact Info

Product

Resources

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Rapid Evolution of Type II Spicules Observed in Goode Solar Telescope On-disk H_α Images