On the periodicity of oscillatory reconnection

McLaughlin, James; Thurgood, Jonathan; MacTaggart, David

doi:10.1051/0004-6361/201220234

Cited by 53 publications

(57 citation statements)

References 67 publications

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“…The oscillatory reconnection is initiated in a self-consistent manner instead of driven manner. In a further study of McLaughlin et al (2012), two distinct periodic phases in the oscillatory oscillation were identified for the first time, i.e., the transient, impulsive phase, and the stationary phase. During the observations of solar flares, very short period radio pulsations were found in many studies (e.g., Kliem et al 2000;Tan et al 2007; also the review by Nakariakov & Melnikov 2009).…”

Section: Conclusion and Discussionmentioning

confidence: 99%

Oscillation of Newly Formed Loops After Magnetic Reconnection in the Solar Chromosphere

Yang

Xiang

2016

ApJL

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With the high spatial and temporal resolution Hα images from the New Vacuum Solar Telescope, we focus on two groups of loops with an X-shaped configuration in the dynamic chromosphere. We find that the anti-directed loops approach each other and reconnect continually. The connectivity of the loops is changed and new loops are formed and stack together. The stacked loops are sharply bent, implying that they are greatly impacted by the magnetic tension force. When another reconnection process takes place, one new loop is formed and stacks with the previously formed ones. Meanwhile, the stacked loops retract suddenly and move toward the balance position, performing an overshoot movement, which led to an oscillation with an average period of about 45 s. The oscillation of newly formed loops after magnetic reconnection in the chromosphere is observed for the first time. We suggest that the stability of the stacked loops is destroyed due to the attachment of the last new loop and then suddenly retract under the effect of magnetic tension. Because of the retraction, another lower loop is pushed outward and performs an oscillation with a period of about 25 s. The different oscillation periods may be due to their difference in three parameters, i.e., loop length, plasma density, and magnetic field strength.

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Section: Conclusion and Discussionmentioning

confidence: 99%

Oscillation of Newly Formed Loops After Magnetic Reconnection in the Solar Chromosphere

Yang

Xiang

2016

ApJL

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“…This was later also studied by in a similar setting, where they performed a parametric study. McLaughlin, Thurgood, and MacTaggart (2012) reported that the period of the oscillatory reconnection depends on the amplitude of the exciting wave, indicating that the waves are essentially non-linear. Pucci, Onofri, and Malara (2014) perturbed an X-point with magnetosonic perturbations, and also found oscillatory reconnection.…”

Section: Periods Generated By the Flarementioning

confidence: 99%

Quasi-periodic Pulsations in Solar and Stellar Flares: An Overview of Recent Results (Invited Review)

2016

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Quasi-periodic pulsations (or QPPs) are periodic intensity variations in the flare emission, across all wavelength bands. In this paper, we review the observational and modelling achievements since the previous review on this topic by Nakariakov and Melnikov (2009). In recent years, it has become clear that QPPs are an inherent feature of solar flares, because almost all flares exhibit QPPs. Moreover, it is now firmly established that QPPs often show multiple periods. We also review possible mechanisms for generating QPPs. Up to now, it has not been possible to conclusively identify the triggering mechanism or cause of QPPs. The lack of this identification currently hampers possible seismological inferences of flare plasma parameters. QPPs in stellar flares have been detected for a long time, and the high quality data of the Kepler mission allows to study the QPP more systematically. However, it has not been conclusively shown whether the time scales of stellar QPPs are different or the same as those in solar flares.

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“…The mechanism giving rise to QPP is not fully understood at present. One possibility pointed out by McLaughlin et al (2012) is that of oscillatory reconnection. The behaviour of oscillatory reconnection is similar to a damped harmonic oscillator and may play a role in generating QPP.…”

Section: Introductionmentioning

confidence: 99%

Oscillations in stellar superflares

Balona¹,

Broomhall²,

Kosovichev³

et al. 2015

Monthly Notices of the Royal Astronomical Society

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Two different mechanisms may act to induce quasi-periodic pulsations (QPP) in wholedisk observations of stellar flares. One mechanism may be magneto-hydromagnetic (MHD) forces and other processes acting on flare loops as seen in the Sun. The other mechanism may be forced local acoustic oscillations due to the high-energy particle impulse generated by the flare (known as 'sunquakes' in the Sun). We analyze shortcadence Kepler data of 257 flares in 75 stars to search for QPP in the flare decay branch or post-flare oscillations which may be attributed to either of these two mechanisms. About 18 percent of stellar flares show a distinct bump in the flare decay branch of unknown origin. The bump does not seem to be a highly-damped global oscillation because the periods of the bumps derived from wavelet analysis do not correlate with any stellar parameter. We detected damped oscillations covering several cycles (QPP), in seven flares on five stars. The periods of these oscillations also do not correlate with any stellar parameter, suggesting that these may be a due to flare loop oscillations. We searched for forced global oscillations which might result after a strong flare. To this end, we investigated the behaviour of the amplitudes of solar-like oscillations in eight stars before and after a flare. However, no clear amplitude change could be detected. We also analyzed the amplitudes of the self-excited pulsations in two δ Scuti stars and one γ Doradus star before and after a flare. Again, no clear amplitude changes were found. Our conclusions are that a new process needs to be found to explain the high incidence of bumps in stellar flare light curves, that flare loop oscillations may have been detected in a few stars and that no conclusive evidence exists as yet for flare induced global acoustic oscillations (starquakes).

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On the periodicity of oscillatory reconnection

Cited by 53 publications

References 67 publications

Oscillation of Newly Formed Loops After Magnetic Reconnection in the Solar Chromosphere

Oscillation of Newly Formed Loops After Magnetic Reconnection in the Solar Chromosphere

Quasi-periodic Pulsations in Solar and Stellar Flares: An Overview of Recent Results (Invited Review)

Oscillations in stellar superflares

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