Quasi-Periodic Pulsations in Solar and Stellar Flares. Review

Kupriyanova, E. G.; Kolotkov, Dmitrii Y.; Nakariakov, V. M.; Kaufman, Anastasiia

doi:10.12737/stp-61202001

Cited by 80 publications

(80 citation statements)

References 130 publications

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“…Long-lived 3 to 5 min pulsations are also observed in sunspots (Sych et al 2012(Sych et al , 2020Battams et al 2019). Quasi-periodic variations in X-rays and gamma-rays from solar and stellar flares are also observed (Van Doorsselaere et al 2016;Kupriyanova et al 2020;Inglis et al 2015;Dennis et al 2017;Hayes et al 2020).…”

Section: Introductionmentioning

confidence: 97%

Periodicities in an active region correlated with Type III radio bursts observed by Parker Solar Probe

Cattell

Glesener

Leiran

et al. 2021

A&A

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Context. Periodicities have frequently been reported across many wavelengths in the solar corona. Correlated periods of ~5 min, comparable to solar p-modes, are suggestive of coupling between the photosphere and the corona. Aims. Our study investigates whether there are correlations in the periodic behavior of Type III radio bursts which are indicative of nonthermal electron acceleration processes, and coronal extreme ultraviolet (EUV) emission used to assess heating and cooling in an active region when there are no large flares. Methods. We used coordinated observations of Type III radio bursts from the FIELDS instrument on Parker Solar Probe (PSP), of EUV emissions by the Solar Dynamics Observatory (SDO) Atmospheric Imaging Assembly (AIA) and white light observations by SDO Helioseismic and Magnetic Image (HMI), and of solar flare X-rays by Nuclear Spectroscopic Telescope Array (NuSTAR) on April 12, 2019. Several methods for assessing periodicities are utilized and compared to validate periods obtained. Results. Periodicities of ~5 min in the EUV in several areas of an active region are well correlated with the repetition rate of the Type III radio bursts observed on both PSP and Wind. Detrended 211 and 171 Å light curves show periodic profiles in multiple locations, with 171 Å peaks sometimes lagging those seen in 211 Å. This is suggestive of impulsive events that result in heating and then cooling in the lower corona. NuSTAR X-rays provide evidence for at least one microflare during the interval of Type III bursts, but there is not a one-to-one correspondence between the X-rays and the Type III bursts. Our study provides evidence for periodic acceleration of nonthermal electrons (required to generate Type III radio bursts) when there were no observable flares either in the X-ray data or the EUV. The acceleration process, therefore, must be associated with small impulsive events, perhaps nanoflares.

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Section: Introductionmentioning

confidence: 97%

Periodicities in an active region correlated with Type III radio bursts observed by Parker Solar Probe

Cattell

Glesener

Leiran

et al. 2021

A&A

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“…The high occurrence rate of short-period QPPs in our sample also serve to constrain the structure and particle acceleration in flares (e.g. Van Doorsselaere et al 2016;Kupriyanova et al 2020;Zimovets et al 2021 and references therein). Future constraints on the electron velocities from QPPs in TESS flares may also be joined with constraints derived from the millimeter using the flare's spectral index, field strength, and source volume to better understand particle acceleration in flares (Mac-Gregor et al 2021;Ramsay et al 2021).…”

Section: Discussionmentioning

confidence: 83%

No Such Thing as a Simple Flare: Substructure and QPPs Observed in a Statistical Sample of 20 Second Cadence TESS Flares

Howard,

MacGregor

2021

Preprint

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A 20 second cadence TESS monitoring campaign of 226 low-mass flare stars during Cycle 3 recorded 3792 stellar flares of ≥10 32 erg. We explore the time-resolved emission and substructure in 440 of the largest flares observed at high signal/noise, 97% of which released energies of ≥10 33 erg. We discover degeneracy present at 2 minute cadence between sharply-peaked and weakly-peaked flares is common, although 20 second cadence breaks these degeneracies. We better resolve the rise phases and find 46% of large flares exhibit substructure during the rise phase. We observe 49 candidate quasi-periodic pulsations (QPP) and confirm 17 at ≥3σ. Most of our QPPs have periods less than 10 minutes, suggesting short period optical QPPs are common. We find QPPs in both the rise and decay phases of flares, including a rise-phase QPP in a large flare from Proxima Cen. We confirm the Davenport et al. ( 2014) template provides a good fit to most classical flares observed at high cadence, although 9% favor Gaussian peaks instead. We characterize the properties of complex flares, finding 17% of complex flares exhibit "peak-bump" morphologies composed of a large, highly impulsive peak followed by a second more gradual Gaussian peak. We also estimate the UVC surface fluences of temperate planets at flare peak and find 1/3 of 10 34 erg flares reach the D90 dose of D. Radiodurans in just 20 seconds in the absence of an atmosphere.

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“…In this Letter, we present the first-ever detection of QPP signals in a stellar superflare simultaneously in the SXR and WL bands, typically associated with thermal and non-thermal emissions from the corona and chromosphere of the star, respectively. We identify a specific relationship between the observed WL and SXR QPP parameters (ratio of the oscillation periods), which could be interpreted as a plausible feature of the equivalent LCR-contour oscillations in a stellar superflare (among at least fifteen physical mechanisms/models that have been proposed to explain QPP in flares, see Zimovets et al 2021;Kupriyanova et al 2020;McLaughlin et al 2018).…”

Section: Introductionmentioning

confidence: 81%

“…An intriguing process not predicted by the standard flare model but commonly observed in solar flares are quasi-periodic pulsations (QPP) of the emitted radiation, which have been detected in all spectral bands (see e.g., Nakariakov & Melnikov 2009;Kupriyanova et al 2020). Typically, QPP appear as subsequent increases and decreases in the emission intensity, usually lasting for several cycles only.…”

Section: Introductionmentioning

confidence: 99%

Multi-wavelength quasi-periodic pulsations in a stellar superflare

Kolotkov,

Nakariakov,

Holt

et al. 2021

Preprint

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We present the first multi-wavelength simultaneous detection of QPP in a superflare (more than a thousand times stronger than known solar flares) on a cool star, in soft X-rays (SXR, with XMM-Newton) and white light (WL, with Kepler). It allowed for the first-ever analysis of oscillatory processes in a stellar flare simultaneously in thermal and non-thermal emissions, conventionally considered to come from the corona and chromosphere of the star, respectively. The observed QPP have periods 1.5 ± 0.15 hours (SXR) and 3 ± 0.6 hours (WL), and correlate well with each other. The unique relationship between the observed parameters of QPP in SXR and WL allowed us to link them with oscillations of the electric current in the flare loop, which directly affect the dynamics of non-thermal electrons and indirectly (via Ohmic heating) the thermal plasma. These findings could be considered in favour of the equivalent LCR-contour model of a flare loop, at least in the extreme conditions of a stellar superflare.

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Quasi-Periodic Pulsations in Solar and Stellar Flares. Review

Cited by 80 publications

References 130 publications

Periodicities in an active region correlated with Type III radio bursts observed by Parker Solar Probe

Periodicities in an active region correlated with Type III radio bursts observed by Parker Solar Probe

No Such Thing as a Simple Flare: Substructure and QPPs Observed in a Statistical Sample of 20 Second Cadence TESS Flares

Multi-wavelength quasi-periodic pulsations in a stellar superflare

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