Spatial structure of azimuthally small-scale MHD waves in one-dimensionally inhomogeneous finite pressure plasma with curved field lines

Petrashchuk, Aleksandr; Klimushkin, D. Yu.

doi:10.12737/szf-61202006

Cited by 2 publications

(1 citation statement)

References 42 publications

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“…In axisymmetric models of the magnetosphere, these waves correspond to oscillations with large azimuthal wave numbers (

m ≫ 1

) (Leonovich & Mazur, 1995; Liu et al., 2013; Rubtsov et al., 2018). These oscillations are as a rule Alfven waves accompanied by high‐energy particle fluxes that are the source of these waves (Petrashchuk & Klimushkin, 2020; Takahashi et al., 1990; Zhou et al., 2016). Such Alfven waves are called “poloidal.” Poloidal Alfven waves are believed to be excited due to various instabilities of high‐energy charged particle fluxes in an inhomogeneous magnetospheric plasma (Dai et al., 2013; Hao et al., 2017; Mann et al., 1999; Zhou et al., 2016; Zong et al., 2017).…”

Section: Introductionmentioning

confidence: 99%

The Field of Shock‐Generated Alfven Oscillations Near the Plasmapause

et al. 2021

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A theoretical interpretation is given for magnetohydrodynamic (MHD) oscillations observed by the GOES and Cluster satellites on November 7, 2004 near the plasmapause (Zong et al., 2009, 2012, https://doi.org/10.1029/2009ja014393, https://doi.org/10.1029/2012ja018024), before and after an interplanetary shock passes through the magnetosphere (about 18:27 UT). It is shown that, after the shock front passage, the MHD oscillation spectra recorded by Cluster (C1) and GOES 12, located respectively inside and outside the plasmasphere, differ significantly. According to our interpretation, these differences are due to the shock wavefront affecting the plasmapause and exciting broadband resonant Alfven waves, thus significantly changing the MHD oscillation spectrum. A model in the form of a plasma cylinder was developed in order to study MHD oscillations in the dayside magnetosphere numerically. An analytical model is proposed for the source of resonant Alfven waves that has the form of two fast magnetosonic wave packets propagating along the plasmapause, resulting from the shock wave/plasmapause interaction. Numerically calculated parameters of Alfven waves excited by a source based on this model show a good agreement with the oscillation parameters observed by satellites.

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“…In axisymmetric models of the magnetosphere, these waves correspond to oscillations with large azimuthal wave numbers (

m ≫ 1

Section: Introductionmentioning

confidence: 99%

The Field of Shock‐Generated Alfven Oscillations Near the Plasmapause

et al. 2021

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Dispersion and spatial structure of the coupled Alfvén and slow magnetosonic oscillations in the Solar corona

Petrashchuk,

Anfinogentov,

Fedenev

et al. 2023

Monthly Notices of the Royal Astronomical Society

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Numerical and analytical analysis of the magnetohydrodynamic (MHD) waves in Solar coronal arcades is performed. A semicylinder slab model of arcade is used where the field lines are represented by half-circles intersecting the photosphere, the magnetic shells are represented by nested coaxial semicylinders. The finite plasma pressure is taken into account. The ‘corrugational’ perturbations are considered, that is, the perturbations with short wavelength in the direction along the arcade. In this limit, there are two oscillation modes, the Alfvén and slow magnetosonic modes, coupled due to the field line curvature. The transverse dispersion of the modes, that is, the dependence of the radial wave vector’s component kr on the wave frequency ω, is considered. It was found that the wave is concentrated in two regions of mode’s existence, where $k_r^2\gt 0$: the Alfvén and magnetosonic transparent regions. On one side, each of them is bounded by the resonance surface, where $k_r^2 \rightarrow \infty$. On the resonance surface, the wave’s frequency is determined by the Alfvén and slow magnetosonic modes dispersion relations, respectively. On the other side, the transparent regions are bounded by cut-off frequencies where $k_{r}^2 =0$. In both transparent regions, the perturbations have both transverse electric field (characteristic for the Alfvén mode) and field aligned velocity (characteristic for the slow mode). The wave structure along the field line for several models of plasma parameters is calculated.

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Spatial structure of azimuthally small-scale MHD waves in one-dimensionally inhomogeneous finite pressure plasma with curved field lines

Cited by 2 publications

References 42 publications

The Field of Shock‐Generated Alfven Oscillations Near the Plasmapause

The Field of Shock‐Generated Alfven Oscillations Near the Plasmapause

Dispersion and spatial structure of the coupled Alfvén and slow magnetosonic oscillations in the Solar corona

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