Magnetic-Island Contraction and Particle Acceleration in Simulated Eruptive Solar Flares

Guidoni, S. E.; DeVore, C. R.; Karpen, J. T.; Lynch, B. J.

doi:10.3847/0004-637x/820/1/60

Cited by 84 publications

(80 citation statements)

References 104 publications

(147 reference statements)

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“…ARMS has been used to study numerous dynamic phenomena in the solar atmosphere, including coronal jets (Pariat et al 2015;Wyper et al 2016;Karpen et al 2017), theinteraction between closed and open fields at streamer boundaries (Edmondson et al 2009(Edmondson et al , 2010aMasson et al 2013;Higginson et al 2017a,b), and the examination of plasmoid-unstable reconnection and magnetic island evolution (Paper I; Guidoni et al 2016;Lynch et al 2016). …”

Section: Numerical Simulationsmentioning

confidence: 99%

Formation and Reconnection of Three-dimensional Current Sheets with a Guide Field in the Solar Corona

Edmondson

Lynch

2017

ApJ

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We analyze a series of three-dimensional magnetohydrodynamic numerical simulations of magnetic reconnection in a model solar corona to study the effect of the guide field component on quasi-steady state interchange reconnection in a pseudostreamer arcade configuration. This work extends the analysis of Edmondson et al. (2010b) by quantifying the mass density enhancement coherency scale in the current sheet associated with magnetic island formation during the nonlinear phase of plasmoid-unstable reconnection. We compare the results of four simulations of a zero, weak, moderate, and a strong guide field, B GF /B 0 = {0.0, 0.1, 0.5, 1.0}, to quantify the plasmoid density enhancement's longitudinal and transverse coherency scales as a function of the guide field strength. We derive these coherency scales from autocorrelation and wavelet analyses, and demonstrate how these scales may be used to interpret the density en-

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Section: Numerical Simulationsmentioning

confidence: 99%

Formation and Reconnection of Three-dimensional Current Sheets with a Guide Field in the Solar Corona

Edmondson

Lynch

2017

ApJ

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“…Early magnetotail studies suggested that magnetic reconnection can happen in an episodic fashion (Coppi et al 1966;Schindler 1974), with subsequent observations supporting this view (Hones et al 1976). In coronal conditions, recent numerical models have shown that magnetic reconnection can occur in a repetitive regime (e.g., Kliem et al 2000;Drake et al 2006;Linton & Longcope 2006;Guidoni et al 2016). Repeated episodes of magnetic reconnection itself could account for the modulation of emission in many different wavelengths.…”

Section: Introductionmentioning

confidence: 89%

“…The large modulation depths of the non-thermal emission during this time suggest that the pulsations are a result of episodic reconnection. The timescale would then be determined by either dynamic or periodic variations of the magnetic reconnection process such as multi-island reconnection in coronal current sheets (Drake et al 2006;Guidoni et al 2016).…”

Section: Discussionmentioning

confidence: 99%

Quasi-Periodic Pulsations During the Impulsive and Decay Phases of an X-Class Flare

Hayes

Gallagher

Dennis

et al. 2016

ApJL

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Quasi-periodic pulsations (QPPs) are often observed in X-ray emission from solar flares. To date, it is unclear what their physical origins are. Here, we present a multi-instrument investigation of the nature of QPP during the impulsive and decay phases of the X1.0 flare of 2013 October 28. We focus on the character of the fine structure pulsations evident in the soft X-ray (SXR) time derivatives and compare this variability with structure across multiple wavelengths including hard X-ray and microwave emission. We find that during the impulsive phase of the flare, high correlations between pulsations in the thermal and non-thermal emissions are seen. A characteristic timescale of ∼20 s is observed in all channels and a second timescale of ∼55 s is observed in the non-thermal emissions. SXR pulsations are seen to persist into the decay phase of this flare, up to 20 minutes after the nonthermal emission has ceased. We find that these decay phase thermal pulsations have very small amplitude and show an increase in characteristic timescale from ∼40 s up to ∼70 s. We interpret the bursty nature of the coexisting multi-wavelength QPPs during the impulsive phase in terms of episodic particle acceleration and plasma heating. The persistent thermal decay phase QPPs are most likely connected with compressive magnetohydrodynamic processes in the post-flare loops such as the fast sausage mode or the vertical kink mode.

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“…To resolve these tearing instabilities and their resulting magnetic islands in numerical simulations, a high resolution at the current sheets is necessary. Recent progress in this area has been made by Karpen et al (2012), Guidoni et al (2016) and Hosteaux et al (2018). They are not present at the front of an inverse CME, but at the rear because this is where a current sheet forms when the CME has the same polarity as the solar wind.…”

Section: Synthetic Satellite At L1mentioning

confidence: 99%

Effect of the solar wind density on the evolution of normal and inverse coronal mass ejections

Hosteaux

Chané

Poedts

2019

A&A

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Context. The evolution of magnetised coronal mass ejections (CMEs) and their interaction with the background solar wind leading to deflection, deformation, and erosion is still largely unclear as there is very little observational data available. Even so, this evolution is very important for the geo-effectiveness of CMEs. Aims. We investigate the evolution of both normal and inverse CMEs ejected at different initial velocities, and observe the effect of the background wind density and their magnetic polarity on their evolution up to 1 AU. Methods. We performed 2.5D (axisymmetric) simulations by solving the magnetohydrodynamic (MHD) equations on a radially stretched grid, employing a block-based adaptive mesh refinement (AMR) scheme based on a density threshold to achieve high resolution following the evolution of the magnetic clouds and the leading bow shocks. All the simulations discussed in the present paper were performed using the same initial grid and numerical methods.Results. The polarity of the internal magnetic field of the CME has a substantial effect on its propagation velocity and on its deformation and erosion during its evolution towards Earth. We quantified the effects of the polarity of the internal magnetic field of the CMEs and of the density of the background solar wind on the arrival times of the shock front and the magnetic cloud. We determined the positions and propagation velocities of the magnetic clouds and thus also the stand-off distance of the leading shock fronts (i.e. the thickness of the magnetic sheath region) and the deformation and erosion of the magnetic clouds during their evolution from the Sun to the Earth. Inverse CMEs were found to be faster than normal CMEs ejected in the same initial conditions, but with smaller stand-off distances. They also have a higher magnetic cloud length, opening angle, and mass. Synthetic satellite time series showed that the shock magnitude is not affected by the polarity of the CME. However, the density peak of the magnetic cloud is dependent on the polarity and, in case of inverse CMEs, also on the background wind density. The magnitude of the z-component of the magnetic field was not influenced by either the polarity or the wind density.

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Magnetic-Island Contraction and Particle Acceleration in Simulated Eruptive Solar Flares

Cited by 84 publications

References 104 publications

Formation and Reconnection of Three-dimensional Current Sheets with a Guide Field in the Solar Corona

Formation and Reconnection of Three-dimensional Current Sheets with a Guide Field in the Solar Corona

Quasi-Periodic Pulsations During the Impulsive and Decay Phases of an X-Class Flare

Effect of the solar wind density on the evolution of normal and inverse coronal mass ejections

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