A Blueprint of State-of-the-art Techniques for Detecting Quasi-periodic Pulsations in Solar and Stellar Flares

Broomhall, Anne-Marie; Davenport, James R. A.; Hayes, Laura A.; Inglis, Andrew; Kolotkov, Dmitrii Y.; McLaughlin, James; Mehta, Tishtrya; Nakariakov, V. M.; Notsu, Yuta; Pascoe, D. J.; Pugh, Chloe E.; Doorsselaere, Tom Van

doi:10.3847/1538-4365/ab40b3

Cited by 43 publications

(60 citation statements)

References 98 publications

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“…Numerous physical effects have been studied in theoretical models and observations of kink oscillations. Bayesian analysis and MCMC sampling provide a flexible and convenient framework to analyse and compare different models, and is particularly useful for non-stationary oscillations such as the recent application to quasi-periodic pulsations in solar and stellar flares (Broomhall et al 2019). The particular components of the model we choose to include reflect the features of the event and the quality of the data.…”

Section: Bayesian Analysismentioning

confidence: 99%

Tracking and Seismological Analysis of Multiple Coronal Loops in an Active Region

Pascoe

Smyrli

Doorsselaere

2020

ApJ

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We present a new method to track the position and evolution of coronal loops designed for observations such as active regions in which multiple loops appear in close proximity or overlap with each other along the observational line of sight. The method is based on modeling a time-distance map containing one or more loops and fitting the modeled map to observational data, as opposed to the commonly used technique of analysing each frame independently. This allows us to control the variability of the model, informed by our physical interpretation, and use the trends present to help constrain the model parameters. We apply our method to an observation of a bundle of coronal loops previously investigated using a spatio-temporal autocorrelation method and compare our results. A benefit of our method is that it provides the time series for the position of the loops which may be used for further analysis using established seismological techniques. We demonstrate this by modeling the oscillation of several loops in response to flaring energy releases that occur during the observation, and find evidence of loop evolution consistent with the Kelvin-Helmholtz instability.

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Section: Bayesian Analysismentioning

confidence: 99%

Tracking and Seismological Analysis of Multiple Coronal Loops in an Active Region

Pascoe

Smyrli

Doorsselaere

2020

ApJ

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“…AFINO was developed as a tool to systematically identify quasiperiodic pulsations in a large number of solar flares. It was one of a suite of techniques blind tested by Broomhall et al (2019), who investigated the performance of different oscillation detection methods on controlled, simulated data sets. Broomhall et al (2019) found that AFINO was a robust method for identifying quasiperiodic pulsations and characterizing the dominant frequency of the pulsations with a particularly low rate of false positives.…”

Section: Data Selection and Analysis Methodsmentioning

confidence: 99%

“…It was one of a suite of techniques blind tested by Broomhall et al (2019), who investigated the performance of different oscillation detection methods on controlled, simulated data sets. Broomhall et al (2019) found that AFINO was a robust method for identifying quasiperiodic pulsations and characterizing the dominant frequency of the pulsations with a particularly low rate of false positives. The AFINO code was developed so that it could be straightforwardly adapted to operate on a variety of temporal series, including magnetospheric data.…”

Section: Data Selection and Analysis Methodsmentioning

confidence: 99%

“…This was recently demonstrated by Murphy et al (2018), who used AFINO to identify and characterize the frequency, amplitude, and azimuthal wave number of discrete ULF waves during a geomagnetic storm observed by the Magnetospheric Multiscale Mission. In this study we utilize AFINO as it systematically characterizes a time series as either broadband or discrete based on a goodness of fit to modeled broadband and discrete spectra with a low rate of false positives (Broomhall et al, 2019). This provides a robust and quantifiable definition of the type of ULF wave Journal of Geophysical Research: Space Physics 10.1029/2020JA027887 allowing for the statistical study of the occurrence of both broadband and discrete ULF wave power within the magnetosphere.…”

Section: The Afino Codementioning

confidence: 99%

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Inner Magnetospheric ULF Waves: The Occurrence and Distribution of Broadband and Discrete Wave Activity

et al. 2020

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Ultralow frequency (ULF) waves are electromagnetic pulsations observed throughout the magnetosphere driven by processes both external and internal to the magnetosphere. Within the magnetosphere, discrete and broadband ULF wave activity can couple to the local plasma via coherent or stochastic wave-particle interactions. These wave-particle interactions can lead to dynamic changes in local plasma including rapid acceleration and transport of radiation belt electrons. Using observations from GOES-15 and the Automated Flare Inference of Oscillations algorithm we investigate the distribution and occurrence of broadband and discrete ULF waves to help understand the relative importance of coherent and stochastic wave-particle interactions. We find that intervals of discrete ULF waves are more commonly identified during slow and low-density solar wind and when B z is near zero. Broadband waves are more commonly identified during periods of active solar wind, including periods of high solar wind speeds and large density perturbations, and large negative B z. We also find that under all solar wind conditions the number of intervals of broadband ULF wave power exceeds that of discrete wave power; for example, ULF wave activity is more likely to be broadband. These results suggest that radial diffusion due to incoherent broadband waves is an important driver of wave-particle interactions, especially during active solar wind conditions. However, the presence of discrete waves during both active and quiet solar wind conditions suggests that these waves and the corresponding wave-particle interactions cannot be ignored, especially since discrete wave-particle interactions tend to be more efficient than radial diffusion.

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“…Detection mechanisms that rely on detrending or model fitting (e.g. Dominique et al 2018;Pascoe et al 2017;Broomhall et al 2019) would benefit from information concerning the underlying flare shape.…”

Section: Introductionmentioning

confidence: 99%

The morphology of average solar flare time profiles from observations of the Sun’s lower atmosphere

Kashapova

Broomhall

Larionova

et al. 2021

Monthly Notices of the Royal Astronomical Society

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We study the decay phase of solar flares in several spectral bands using a method based on that successfully applied to white light flares observed on an M4 dwarf. We selected and processed 102 events detected in the Sun-as-a-star flux obtained with SDO/AIA images in the 1600 Å and 304 Å channels and 54 events detected in the 1700 Å channel. The main criterion for the selection of time profiles was a slow, continuous flux decay without significant new bursts. The obtained averaged time profiles were fitted with analytical templates, using different time intervals, that consisted of a combination of two independent exponents or a broken power law. The average flare profile observed in the 1700 Å channel decayed more slowly than the average flare profile observed on the M4 dwarf. As the 1700 Å emission is associated with a similar temperature to that usually ascribed to M dwarf flares, this implies that the M dwarf flare emission comes from a more dense layer than solar flare emission in the 1700 Å band. The cooling processes in solar flares were best described by the two exponents model, fitted over the intervals t1=[0, 0.5]t1/2 and t2=[3, 10]t1/2 where t1/2 is time taken for the profile to decay to half the maximum value. The broken power law model provided a good fit to the first decay phase, as it was able to account for the impact of chromospheric plasma evaporation, but it did not successfully fit the second decay phase.

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A Blueprint of State-of-the-art Techniques for Detecting Quasi-periodic Pulsations in Solar and Stellar Flares

Cited by 43 publications

References 98 publications

Tracking and Seismological Analysis of Multiple Coronal Loops in an Active Region

Tracking and Seismological Analysis of Multiple Coronal Loops in an Active Region

Inner Magnetospheric ULF Waves: The Occurrence and Distribution of Broadband and Discrete Wave Activity

The morphology of average solar flare time profiles from observations of the Sun’s lower atmosphere

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