High frequency and high wavenumber solar oscillations

We determine the frequencies of solar oscillations covering a wide range of degree (100 < l < 4000) and frequency (1.5 < ν < 10 mHz) using the ring diagram technique applied to power spectra obtained from MDI (Michelson Doppler Imager) data. The f-mode ridge extends up to l ≈ 3000, where the line width becomes very large, implying a damping time which is comparable to the time period. The frequencies of high degree f-modes are significantly different from those given by the simple dispersion relation ω = gk. The f-mode peaks in power spectra are distinctly asymmetric and use of asymmetric profile increases the fitted frequency bringing them closer to the frequencies computed for a solar model. Subject headings: Sun: oscillations; Sun: chromosphere