Observational Signatures of a Kink-unstable Coronal Flux Rope Using Hinode/EIS

Snow, Ben; Botha, G. J. J.; Régnier, Stéphane; Morton, R. J.; Verwichte, E.; Young, Peter R.

doi:10.3847/1538-4357/aa6d0e

Cited by 8 publications

(12 citation statements)

References 30 publications

(54 reference statements)

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“…In panel 10b, the directions and values of velocity of rotating plasma are shown by the colored arrows, and the magnetic field lines passing through discrete points on the z-axis are given by curves. The values of plasma velocity field around the MFR is subsonic with the exception of a small region under the MFR, and the direction of the velocity field shows simultaneous downward and upward flow, which is consistent with the red-and blueshifts observed in synthetic Doppler map generated from a 3D simulation of a kinked straight MFR (Pinto et al 2016;Snow et al 2017). In addition, the rotations on left and right regions of the MFR are anticlockwise when we look downward from above.…”

Section: Internal Kink Instabilitiessupporting

confidence: 83%

Parametric study on kink instabilities of twisted magnetic flux ropes in the solar atmosphere

Keppens

Roussev

Lin

2017

A&A

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Aims. Twisted magnetic flux ropes (MFRs) in the solar atmosphere have been researched extensively because of their close connection to many solar eruptive phenomena, such as flares, filaments, and coronal mass ejections (CMEs). In this work, we performed a set of 3D isothermal magnetohydrodynamic (MHD) numerical simulations, which use analytical twisted MFR models and study dynamical processes parametrically inside and around current-carrying twisted loops. We aim to generalize earlier findings by applying finite plasma β conditions. Methods. Inside the MFR, approximate internal equilibrium is obtained by pressure from gas and toroidal magnetic fields to maintain balance with the poloidal magnetic field. We selected parameter values to isolate best either internal or external kink instability before studying complex evolutions with mixed characteristics. We studied kink instabilities and magnetic reconnection in MFRs with low and high twists. Results. The curvature of MFRs is responsible for a tire tube force due to its internal plasma pressure, which tends to expand the MFR. The curvature effect of toroidal field inside the MFR leads to a downward movement toward the photosphere. We obtain an approximate internal equilibrium using the opposing characteristics of these two forces. A typical external kink instability totally dominates the evolution of MFR with infinite twist turns. Because of line-tied conditions and the curvature, the central MFR region loses its external equilibrium and erupts outward. We emphasize the possible role of two different kink instabilities during the MFR evolution: internal and external kink. The external kink is due to the violation of the Kruskal-Shafranov condition, while the internal kink requires a safety factor q = 1 surface inside the MFR. We show that in mixed scenarios, where both instabilities compete, complex evolutions occur owing to reconnections around and within the MFR. The S-shaped structures in current distributions appear naturally without invoking flux emergence. Magnetic reconfigurations common to eruptive MFRs and flare loop systems are found in our simulations.

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Section: Internal Kink Instabilitiessupporting

confidence: 83%

Parametric study on kink instabilities of twisted magnetic flux ropes in the solar atmosphere

Keppens

Roussev

Lin

2017

A&A

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“…A more precise timing and association between IS energetic electrons and X-ray emitting electrons will allow in particular to re-investigate the relationship between the in-situ electron spectra and the electron spectra at the sun deduced from X -ray observations (see (e.g., Krucker et al 2007). In this respect, new models have been developed in recent years that couple the large-scale evolution of magnetic fields with the acceleration of particles and the injection of these particles into the open magnetic field (Snow et al 2017).…”

Section: Investigations On the Properties And Origin(s) Of Sepsmentioning

confidence: 99%

Models and data analysis tools for the Solar Orbiter mission

Rouillard

Pinto

Vourlidas

et al. 2020

A&A

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Context. The Solar Orbiter spacecraft will be equipped with a wide range of remote-sensing (RS) and in-situ (IS) instruments to record novel and unprecedented measurements of the solar atmosphere and the inner heliosphere. To take full advantage of these new datasets, tools and techniques must be developed to ease multi-instrument and multi-spacecraft studies. In particular the currently inaccessible low solar corona below two solar radii can only be observed remotely. Furthermore techniques must be used to retrieve coronal plasma properties in time and in three dimensional (3D) space. Solar Orbiter will run complex observation campaigns that provide interesting opportunities to maximise the likelihood of linking IS data to their source region near the Sun. Several RS instruments can be directed to specific targets situated on the solar disk just days before data acquisition. To compare IS and RS, data we must improve our understanding of how heliospheric probes magnetically connect to the solar disk. Aims. The aim of the present paper is to briefly review how the current modelling of the Sun and its atmosphere can support Solar Orbiter science. We describe the results of a community-led effort by European Space Agency (ESA)'s Modelling and Data Analysis Working Group (MADAWG) to develop different models, tools, and techniques deemed necessary to test different theories for the physical processes that may occur in the solar plasma. The focus here is on the large scales and little is described with regards to kinetic processes. To exploit future IS and RS data fully, many techniques have been adapted to model the evolving 3D solar magneto-plasma from the solar interior to the solar wind. A particular focus in the paper is placed on techniques that can estimate how Solar Orbiter will connect magnetically through the complex coronal magnetic fields to various photospheric and coronal features in support of spacecraft operations and future scientific studies. Methods. Recent missions such as STEREO, provided great opportunities for RS, IS, and multi-spacecraft studies. We summarise the achievements and highlight the challenges faced during these investigations, many of which motivated the Solar Orbiter mission. We present the new tools and techniques developed by the MADAWG to support the science operations and the analysis of the data from the many instruments on Solar Orbiter. Results. This article reviews current modelling and tool developments that ease the comparison of model results with RS and IS data made available by current and upcoming missions. It also describes the modelling strategy to support the science operations and subsequent exploitation of Solar Orbiter data in order to maximise the scientific output of the mission. Conclusions. The on-going community effort presented in this paper has provided new models and tools necessary to support mission operations as well as the science exploitation of the Solar Orbiter data. The tools and techniques will no doubt evolve significantly as we refine our proc...

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“…That is why thermal emission from reconnecting twisted loops has been studied by combining MHD simulations with radiative simulations of thermal continuum emission (e.g. Botha et al, 2012;Pinto et al, 2015;Snow et al, 2017). Investigation of thermal continuum emission produced by the reconnecting twisted loops explains why the observed twist is usually quite weak, with twist angle often observed to be smaller than critical angle required for kink-instability.…”

Section: Mhdtp Model Of Reconnecting Twisted Coronal Loopmentioning

confidence: 99%

Combining MHD and kinetic modelling of solar flares

Gordovskyy

Browning

Pinto

2019

Advances in Space Research

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Solar flares are explosive events in the solar corona, representing fast conversion of magnetic energy into thermal and kinetic energy, and hence radiation, due to magnetic reconnection. Modelling is essential for understanding and predicting these events. However, self-consistent modelling is extremely difficult due to the vast spatial and temporal scale separation between processes involving thermal plasma (normally considered using magnetohydrodynamic (MHD) approach) and non-thermal plasma (requiring a kinetic approach). In this mini-review we consider different approaches aimed at bridging the gap between fluid and kinetic modelling of solar flares. Two types of approaches are discussed: combined MHD/test-particle (MHDTP) models, which can be used for modelling the flaring corona with relatively small numbers of energetic particles, and hybrid fluid-kinetic methods, which can be used for modelling stronger events with higher numbers of energetic particles. Two specific examples are discussed in more detail: MHDTP models of magnetic reconnection and particle acceleration in kink-unstable twisted coronal loops, and a novel reduced-kinetic model of particle transport.

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Observational Signatures of a Kink-unstable Coronal Flux Rope Using Hinode/EIS

Cited by 8 publications

References 30 publications

Parametric study on kink instabilities of twisted magnetic flux ropes in the solar atmosphere

Parametric study on kink instabilities of twisted magnetic flux ropes in the solar atmosphere

Models and data analysis tools for the Solar Orbiter mission

Combining MHD and kinetic modelling of solar flares

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