Anisotropic Magnetized Asteroseismic Waves
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arXiv
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| Format: | Preprint |
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2024
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| author | Tripathi, B. Mitra, Dhrubaditya |
| author_facet | Tripathi, B. Mitra, Dhrubaditya |
| contents | We solve for waves in a polytropic, stratified plasmas with a spatially varying background magnetic field that points along a horizontal $x$-direction, and with gravity that is directed along the vertical $z$-direction. Force balance determines the magnitude of the background magnetic field, $B_0^2 \sim z^{n+1}$, where $n$ is the polytropic index. Using numerical and asymptotic methods, we deduce an explicit dispersion relation for fast pressure-driven waves: $Ω^2 \sim K\left(2m+n\right) \left[1 + (1/M_\mathrm{A})^2 (4-2γ+\cos^2θ-3\cos^4θ)/4 \right]$. Here, $Ω$ is the frequency, $K$ the wavenumber, $θ$ the angle the wave-vector makes with the background magnetic field, $M_\mathrm{A}$ the Alfvénic Mach number, and $m$ an integer representing the eigenstate. We discuss roles of such an explicit formula in asteroseismology. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2405_01856 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Anisotropic Magnetized Asteroseismic Waves Tripathi, B. Mitra, Dhrubaditya Solar and Stellar Astrophysics Fluid Dynamics Plasma Physics Space Physics We solve for waves in a polytropic, stratified plasmas with a spatially varying background magnetic field that points along a horizontal $x$-direction, and with gravity that is directed along the vertical $z$-direction. Force balance determines the magnitude of the background magnetic field, $B_0^2 \sim z^{n+1}$, where $n$ is the polytropic index. Using numerical and asymptotic methods, we deduce an explicit dispersion relation for fast pressure-driven waves: $Ω^2 \sim K\left(2m+n\right) \left[1 + (1/M_\mathrm{A})^2 (4-2γ+\cos^2θ-3\cos^4θ)/4 \right]$. Here, $Ω$ is the frequency, $K$ the wavenumber, $θ$ the angle the wave-vector makes with the background magnetic field, $M_\mathrm{A}$ the Alfvénic Mach number, and $m$ an integer representing the eigenstate. We discuss roles of such an explicit formula in asteroseismology. |
| title | Anisotropic Magnetized Asteroseismic Waves |
| topic | Solar and Stellar Astrophysics Fluid Dynamics Plasma Physics Space Physics |
| url | https://arxiv.org/abs/2405.01856 |