Coronal magnetic loops

Зайцев, В. В.; Stepanov, A. V.

doi:10.1070/pu2008v051n11abeh006657

Cited by 89 publications

(39 citation statements)

References 159 publications

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“…For different values of the parameters, the model gives periods from a fraction of a second to a few minutes (e.g. Zaitsev and Stepanov 2008). The LCR oscillations of a flaring magnetic loop can produce QPPs of both thermal and non-thermal emission.…”

Section: Equivalent Lcr Contourmentioning

confidence: 99%

Modelling Quasi-Periodic Pulsations in Solar and Stellar Flares

et al. 2018

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Solar flare emission is detected in all EM bands and variations in flux density of solar energetic particles. Often the EM radiation generated in solar and stellar flares shows a pronounced oscillatory pattern, with characteristic periods ranging from a fraction of a second to several minutes. These oscillations are referred to as quasi-periodic pulsations (QPPs), to emphasise that they often contain apparent amplitude and period modulation. We review the current understanding of quasi-periodic pulsations in solar and stellar flares. In particular, we focus on the possible physical mechanisms, with an emphasis on the underlying physics that generates the resultant range of periodicities. These physical mechanisms include MHD oscillations, self-oscillatory mechanisms, oscillatory reconnection/reconnection reversal, wave-driven reconnection, two loop coalescence, MHD flow over-stability, the equivalent LCR-contour mechanism, and thermal-dynamical cycles. We also provide a histogram of all QPP events published in the literature at this time. The occurrence of QPPs puts additional constraints on the interpretation and understanding of the fundamental processes operating in flares, e.g. magnetic energy liberation and particle acceleration. Therefore, a full understanding of QPPs is essential in order to work towards an integrated model of solar and stellar flares.

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Section: Equivalent Lcr Contourmentioning

confidence: 99%

Modelling Quasi-Periodic Pulsations in Solar and Stellar Flares

et al. 2018

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“…Responding to the intensive research activity in the MHD wave studies, there are a number of comprehensive reviews of different aspects of the topic, see, e.g. Zaitsev and Stepanov (2008); Petrosyan et al (2010); Banerjee et al (2011);Patsourakos and Vourlidas (2012a); De Moortel and Nakariakov (2012); Stepanov et al (2012); Mathioudakis et al (2013); Liu and Ofman (2014) for most recent "solar" reviews, and Guglielmi and Pokhotelov (1996); Walker (2005); Alperovich and Fedorov (2007) for "magnetospheric" reviews. Regrettably, in the majority of cases MHD wave phenomena in the solar corona and the Earth's magnetosphere are studied separately.…”

Section: Introductionmentioning

confidence: 99%

Magnetohydrodynamic Oscillations in the Solar Corona and Earth’s Magnetosphere: Towards Consolidated Understanding

Nakariakov

Пилипенко

Heilig³

et al. 2016

Space Sci Rev

185

128

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Magnetohydrodynamic (MHD) oscillatory processes in different plasma systems, such as the corona of the Sun and the Earth's magnetosphere show interesting similarities and differences, which so far received little attention and remain underexploited. The successful commissioning within the past ten years of SDO, Hinode, STEREO and THEMIS spacecraft, in combination with matured analysis of data from earlier spacecraft (Wind, SOHO, ACE, Cluster, TRACE and RHESSI) makes it very timely to survey the breadth of observations giving evidence for MHD oscillatory processes in solar and space plasmas, and state-of-the-art theoretical modelling. The paper reviews several important topics, such as Alfvénic resonances and mode conversion; MHD waveguides, such as the magnetotail, coronal loops, coronal streamers; mechanisms for periodicities produced in energy releases during substorms and solar flares, possibility of Alfvénic resonators along open field lines; possible drivers of MHD waves; diagnostics of plasmas with MHD waves; interaction of MHD waves with partly-ionised boundaries (ionosphere and chromosphere). The review is mainly oriented to specialists in magnetospheric physics and solar physics, but not familiar with specifics of the adjacent research fields.

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“…Nakariakov 2007;Zaitsev & Stepanov 2008;Nakariakov & Melnikov 2009;Nakariakov et al 2010b, for recent comprehensive reviews). These oscillatory variations of emission generated in energy releases are detected in the radio band, white light, soft and hard X-rays, and gamma-rays, and usually have periods from a fraction of a second to several minutes (e.g.…”

Section: Introductionmentioning

confidence: 99%

Multi-mode quasi-periodic pulsations in a solar flare

Kolotkov

Nakariakov

Kupriyanova

et al. 2015

A&A

102

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Context. Quasi-periodic pulsations (QPP) of the electromagnetic radiation emitted in solar and stellar flares are often detected in microwave, white light, X-ray, and gamma-ray bands. Mechanisms for QPP are intensively debated in the literature. Previous studies revealed that QPP may manifest non-linear, non-stationary and, perhaps, multi-modal processes operating in flares. Aims. We study QPP of the microwave emission generated in an X3.2-class solar flare on 14 May, 2013, observed with the Nobeyama Radioheliograph (NoRH), aiming to reveal signatures of the non-linear, non-stationary, and multi-modal processes in the signal. Methods. The NoRH correlation signal obtained at the 17 GHz intensity has a clear QPP pattern. The signal was analysed with the Hilbert-Huang transform (HHT) that allows one to determine its instant amplitude and frequency, and their time variation. Results. It was established that the QPP consists of at least three well-defined intrinsic modes, with the mean periods of 15, 45, and 100 s. All the modes have quasi-harmonic behaviour with different modulation patterns. The 100 s intrinsic mode is a decaying oscillation, with the decay time of 250 s. The 15 s intrinsic mode shows a similar behaviour, with the decay time of 90 s. The 45 s mode has a wave-train behaviour. Conclusions. Dynamical properties of detected intrinsic modes indicate that the 100 s and 15 s modes are likely to be associated with fundamental kink and sausage modes of the flaring loop, respectively. The 100 s oscillation could also be caused by the fundamental longitudinal mode, while this interpretation requires the plasma temperature of about 30 million K and hence is not likely. The 45 s mode could be the second standing harmonics of the kink mode.

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Coronal magnetic loops

Cited by 89 publications

References 159 publications

Modelling Quasi-Periodic Pulsations in Solar and Stellar Flares

Modelling Quasi-Periodic Pulsations in Solar and Stellar Flares

Magnetohydrodynamic Oscillations in the Solar Corona and Earth’s Magnetosphere: Towards Consolidated Understanding

Multi-mode quasi-periodic pulsations in a solar flare

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