Self-organization of magnetoacoustic waves in a thermally unstable environment

Chin, Robert; Verwichte, E.; Rowlands, G.; Nakariakov, V. M.

doi:10.1063/1.3314721

Cited by 57 publications

(71 citation statements)

References 21 publications

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“…It may either lead to the nonlinear dissipation that is much stronger for the same value of the transport coefficients than the dissipation in the linear regime (see, e.g. Afanasyev & Nakariakov 2015b), or to the occurrence of a stationary regime similar to described in Chin et al (2010), in which the wave has a sawtooth shape but the amplitude does not decay. This phenomenon could be understood in terms of the wave spectrum evolution.…”

Section: Discussionmentioning

confidence: 99%

Effect of Local Thermal Equilibrium Misbalance on Long-wavelength Slow Magnetoacoustic Waves

Nakariakov

Afanasyev

Kumar

et al. 2017

ApJ

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Evolution of slow magnetoacoustic waves guided by a cylindrical magnetic flux tube that represents a coronal loop or plume, is modelled accounting for the effects of finite gas pressure, weak nonlinearity, dissipation by thermal conduction and viscosity, and the misbalance between the cooling by optically thin radiation and unspecified heating of the plasma. An evolutionary equation of the Burgers-Malthus type is derived. It is shown that the cooling/heating misbalance, determined by the derivatives of the combined radiative cooling and heating function, with respect to the density, temperature and magnetic field at the thermal equilibrium affect the wave rather strongly. This effect may either cause additional damping, or counteract it, or lead to the gradual amplification of the wave. In the latter case the coronal plasma acts as an active medium for the slow magnetoacoustic waves. The effect of the cooling/heating misbalance could be important for coronal slow waves, and could be responsible for certain discrepancies between theoretical results and observations, in particular the increased or decreased damping lengths and times, detection of the waves at certain heights only, and excitation of compressive oscillations. The results obtained open up a possibility for the diagnostics of the coronal heating function by slow magnetoacoustic waves.

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Section: Discussionmentioning

confidence: 99%

Effect of Local Thermal Equilibrium Misbalance on Long-wavelength Slow Magnetoacoustic Waves

Nakariakov

Afanasyev

Kumar

et al. 2017

ApJ

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“…Chin and co-authors in Ref. [3] include heating and radiative cooling but consider perturbations over constant background. The validity of this approach should be carefully investigated in view of that the external source makes the background temperature nonuniform.…”

Section: Nonlinear Effects Which Associate With the Intense Magnetoacmentioning

confidence: 99%

“…(15) from Ref. [3] with θ = π/2, zero thermal conduction and zero nonlinear term associated with the heating-cooling function. Chin and co-authors in Ref.…”

Section: Nonlinear Effects Which Associate With the Intense Magnetoacmentioning

confidence: 99%

“…The nonlinear dynamics of magnetoacoustic waves in a thermally active and dissipative plasma has been studied analytically * corresponding author; e-mail: anpe@mif.pg.gda.pl by Chin and co-authors in Ref. [3]. Authors of Ref.…”

Section: Introductionmentioning

confidence: 99%

“…Authors of Ref. [3] have derived the generic nonlinear evolutionary equation which describes perturbations in active medium and have concluded about possibility of self-organization of MHD disturbances. In particular, it has been discovered that the formation of shock waves depends strongly on the type of the heating-cooling function.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

On the Nonlinear Effects of Magnetoacoustic Perturbations in Optically Thin Quasi-Isentropic Plasmas

Perelomova

Ratkowski

2018

Acta Phys. Pol. A

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Nonlinear effects of planar magnetosound perturbations in a plasma are discussed. Plasma is non-adiabatic due to optically thin radiation and external heating. For these reasons, thermal instability of a plasma may appear which makes it acoustically active. The plasma is assumed to be initially homogeneous ideal gas with infinite electrical conductivity permeated by a straight magnetic field which is orthogonal to the trajectories of gas particles. The instantaneous dynamic equations which describe nonlinear effects of intense sound in quasi-isentropic plasma, are derived. Nonlinear interaction of periodic and aperiodic magnetoacoustic perturbations with the non-wave modes, are discussed. The conclusions concern dissipative or active behavior of magnetoacoustic perturbations which is determined by the kind of the heating-cooling function.

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The description of non‐linear interactions of wave and non‐wave modes in a non‐adiabatic plasma flow

Perelomova

2021

Contributions to Plasma Physics

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The method of derivation of non-linear equations for interacting modes is explained and applied to a plasma's flow affected by a magnetic field. It is based on the linear projecting of the total perturbation field into specific variations of variables in individual modes of a flow. The method may be applied in many examples of fluid flows with different mechanisms of non-adiabaticity. It is of special importance in complex flows with large number of different modes. A flow of an ionized gas is one of the examples of such flows: it incorporatesfast, slow magnetosonic modes, the Alfvén mode and the entropy mode. In the frames of this study, the wave vector may form an arbitrary angle with the straight equilibrium magnetic field. Thermal conduction, dynamic viscosity and a generic heating-cooling function, which is responsible for an energy inflow and radiative losses, are taken into account. Variable and plasma-β, diversity of the wave modes and a balance of different mechanisms of non-adiabaticity make the description of non-linear interaction of modes special. The non-linear excitation of the magnetosonic mode by the entropy mode is considered as an example.

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Self-organization of magnetoacoustic waves in a thermally unstable environment

Cited by 57 publications

References 21 publications

Effect of Local Thermal Equilibrium Misbalance on Long-wavelength Slow Magnetoacoustic Waves

Effect of Local Thermal Equilibrium Misbalance on Long-wavelength Slow Magnetoacoustic Waves

On the Nonlinear Effects of Magnetoacoustic Perturbations in Optically Thin Quasi-Isentropic Plasmas

The description of non‐linear interactions of wave and non‐wave modes in a non‐adiabatic plasma flow

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