Distortion of high-degree solar p-mode eigenfunctions by latitudinal differential rotation

Abstract

view Abstract Citations (63) References (5) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Distortion of High-Degree Solar p-Mode Eigenfunctions by Latitudinal Differential Rotation Woodard, Martin F. Abstract The eigenfunctions of nonradial oscillation of the sun depart from their customarily assumed spherical harmonic form as a result of solar rotation. This paper treats the effect on oscillation eigenfunctions of slow, axisymmetric differential rotation which is also mirror symmetric across the solar equatorial plane. A given oscillation eigenfunction, perturbed by rotation, can be expressed as a superposition of eigenfunctions of a (hypothetical) nonrotating state of the sun. The assumption of axialsymmetry implies that each of the superposed functions has the same azimuthal order, m, while mirror symmetry dictates that the values of l, the spherical harmonic degree, involved in the superposition be either all odd or all even. The treatment here is further specialized to the case of high-degree p- and f-mode oscillations, on which the effect of the Coriolis acceleration is small. It is shown that, by ignoring the Coriolis effect and making other sensible approximations, an analytic expression can be obtained for the rotationally distorted mode eigenfunctions, which is expected to be a good approximation for typical solar oscillations of degree l greater than 100. The effect of the calculated mode distortion on the measurement of solar rotation is explored. Publication: The Astrophysical Journal Pub Date: December 1989 DOI: 10.1086/168206 Bibcode: 1989ApJ...347.1176W Keywords: Eigenvectors; Solar Oscillations; Solar Rotation; Axes Of Rotation; Formalism; Spherical Harmonics; Solar Physics; SUN: OSCILLATIONS; SUN: ROTATION full text sources ADS |