Modelling Solar Oscillation Power Spectra: II. Parametric Model of Spectral Lines Observed in Doppler Velocity Measurements

摘要

We describe a global parametric model for the observed power spectra of solaroscillations of intermediate and low degree. A physically motivatedparameterization is used as a substitute for a direct description of modeexcitation and damping as these mechanisms remain poorly understood. The modelis targeted at the accurate fitting of power spectra coming from Dopplervelocity measurements and uses an adaptive response function that accounts forboth the vertical and horizontal components of the velocity field on the solarsurface and for possible instrumental and observational distortions. The modelis continuous in frequency, can easily be adapted to intensity measurements andextends naturally to the analysis of high-frequency pseudo modes (interferencepeaks at frequencies above the atmospheric acoustic cutoff).