Year: 2024
Type: article
Abstract: We solve for waves in a polytropic, stratified plasma with a spatially varying background magnetic field that points along the 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 ∼ 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 ∼ K 2 m + n [ 1 + 1 / M A 2 ( 4 − 2 γ + cos 2 θ − 3 cos 4 θ ) / 4 ] . Here, Ω is the frequency, K is the wavenumber, θ is the angle the wavevector makes with the background magnetic field, M A is the Alfvénic Mach number, and m is an integer representing the eigenstate. We discuss the roles of such an explicit formula in asteroseismology.
Source: The Astrophysical Journal
Authors: B. Tripathi, Dhrubaditya Mitra
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $4,499
OpenAlex ID: W4404338532