Three-Dimensional Simulation of Solar Emerging Flux Using the Earth Simulator I. Magnetic Rayleigh-Taylor Instability at the Top of the Emerging Flux as the Origin of Filamentary Structure

Isobe, Hiroaki; Miyagoshi, Takehiro; Shibata, Kazunari; Yokoyama, T.

doi:10.1093/pasj/58.2.423

Cited by 61 publications

(42 citation statements)

References 77 publications

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“…This non-linear phase agrees qualitatively with the observations of turbulent plumes and bubbles in prominences (Isobe et al 2005;Berger et al 2008Berger et al , 2010Berger et al , 2011Heinzel et al 2008;Ryutova et al 2010) and has even been used to infer plasma properties from observational features (Hillier et al 2012b). The presence of the RTI has also been confirmed numerically in more general prominence models with 3D geometry (Isobe et al 2006;Hillier et al 2011Hillier et al , 2012a.…”

Section: Introductionsupporting

confidence: 81%

Rayleigh-Taylor instability in partially ionized compressible plasmas: One fluid approach

Díaz

Khomenko

Collados

2014

A&A

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Aims. We study the modification of the classical criterion for the linear onset and growth rate of the Rayleigh-Taylor instability (RTI) in a partially ionized (PI) plasma in the one-fluid description by considering a generalized induction equation. Methods. The governing linear equations and appropriate boundary conditions, including gravitational terms, are derived and applied to the case of the RTI in a single interface between two partially ionized plasmas. The boundary conditions lead to an equation for the frequencies in which some have positive complex parts, marking the appearance of the RTI. We study the ambipolar term alone first, extending the result to the full induction equation later. Results. The configuration is always unstable because of the presence of a neutral species. In the classical stability regime, the growth rate is small, since the collisions prevent the neutral fluid to fully develop the RTI. For parameters in the classical instability regime, the growth rate is lowered, but the differences with the compressible MHD case are small for the considered theoretical values of the collision frequencies and diffusion coefficients for solar prominences. Conclusions. The PI modifies some aspects of the linear RTI instability, since it takes into account that neutrals do not feel the stabilizing effect of the magnetic field. For the set of parameters representative for solar prominences, our model gives the resulting timescale comparable to observed lifetimes of RTI plumes.

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Section: Introductionsupporting

confidence: 81%

Rayleigh-Taylor instability in partially ionized compressible plasmas: One fluid approach

Díaz

Khomenko

Collados

2014

A&A

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“…This is consistent with the RT-CD theory because larger toroidal magnetic field gives smaller U 2 and hence the RT effect is weaker. As the flux tube emerges from the convection zone to the solar corona, a filamentary structure can form at the top of the emerging flux tube as a result of MRT instability 43,44 under solar gravity. The filamentary structure is found to be parallel to the surface magnetic field, consistent with the interchange mode of MRT instability.…”

Section: Summary and Discussionmentioning

confidence: 99%

A hybrid Rayleigh-Taylor-current-driven coupled instability in a magnetohydrodynamically collimated cylindrical plasma with lateral gravity

Zhai

Bellan

2016

Physics of Plasmas

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We present an MHD theory of Rayleigh-Taylor instability on the surface of a magnetically confined cylindrical plasma flux rope in a lateral external gravity field. The Rayleigh-Taylor instability is found to couple to the classic current-driven instability, resulting in a new type of hybrid instability that cannot be described by either of the two instabilities alone. The lateral gravity breaks the axisymmetry of the system and couples all azimuthal modes together. The coupled instability, produced by combination of helical magnetic field, curvature of the cylindrical geometry, and lateral gravity, is fundamentally different from the classic magnetic Rayleigh-Taylor instability occurring at a two-dimensional planar interface. The theory successfully explains the lateral Rayleigh-Taylor instability observed in the Caltech plasma jet experiment [Moser and Bellan, Nature 482, 379 (2012)]. Potential applications of the theory include magnetic controlled fusion, solar emerging flux, solar prominences, coronal mass ejections, and other space and astrophysical plasma processes.

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“…In fact, the emergence of the axis proceeds more efficiently when a curved (convex-up) flux tube is initially assumed MacTaggart and Hood, 2009). Archontis et al (2004Archontis et al ( , 2005Archontis et al ( , 2007, Isobe et al (2005Isobe et al ( , 2006, and Galsgaard et al (2005Galsgaard et al ( , 2007 have studied the interaction of emerging and preexisting fields in various three-dimensional configurations (see Section 4.3). A series of works done by Manchester (Manchester IV, 2001;Manchester IV et al, 2004;Manchester IV, 2007) have shown the origin of shear flows observed on the surface (see Section 4.3).…”

Section: Latest Progressmentioning

confidence: 99%

Solar Flares: Magnetohydrodynamic Processes

Shibata

Magara

2011

Living Rev. Solar Phys.

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762

647

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This paper outlines the current understanding of solar flares, mainly focused on magnetohydrodynamic (MHD) processes responsible for producing a flare. Observations show that flares are one of the most explosive phenomena in the atmosphere of the Sun, releasing a huge amount of energy up to about 10 32 erg on the timescale of hours. Flares involve the heating of plasma, mass ejection, and particle acceleration that generates high-energy particles. The key physical processes for producing a flare are: the emergence of magnetic field from the solar interior to the solar atmosphere (flux emergence), local enhancement of electric current in the corona (formation of a current sheet), and rapid dissipation of electric current (magnetic reconnection) that causes shock heating, mass ejection, and particle acceleration. The evolution toward the onset of a flare is rather quasi-static when free energy is accumulated in the form of coronal electric current (field-aligned current, more precisely), while the dissipation of coronal current proceeds rapidly, producing various dynamic events that affect lower atmospheres such as the chromosphere and photosphere. Flares manifest such rapid dissipation of coronal current, and their theoretical modeling has been developed in accordance with observations, in which numerical simulations proved to be a strong tool reproducing the time-dependent, nonlinear evolution of a flare. We review the models proposed to explain the physical mechanism of flares, giving an comprehensive explanation of the key processes mentioned above. We start with basic properties of flares, then go into the details of energy build-up, release and transport in flares where magnetic reconnection works as the central engine to produce a flare.

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Three-Dimensional Simulation of Solar Emerging Flux Using the Earth Simulator I. Magnetic Rayleigh-Taylor Instability at the Top of the Emerging Flux as the Origin of Filamentary Structure

Cited by 61 publications

References 77 publications

Rayleigh-Taylor instability in partially ionized compressible plasmas: One fluid approach

Rayleigh-Taylor instability in partially ionized compressible plasmas: One fluid approach

A hybrid Rayleigh-Taylor-current-driven coupled instability in a magnetohydrodynamically collimated cylindrical plasma with lateral gravity

Solar Flares: Magnetohydrodynamic Processes

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