Sun-as-a-star observations: Evidence for degree dependence of changes in damping of low- ℓ p modes along the solar cycle

The nature of the Sun-as-a-star observations is such that for changes measured at fixed frequency, or for changes averaged across the same range in frequency, any ℓ dependence present carries information on the latitudinal distribution of the agent (i.e., the activity) responsible for those changes.

Methods.We split the 9.5-yr timeseries into contiguous 108-d pieces, and determine mean changes in the damping of, power in, and energy supplied to the modes through the solar cycle. We also apply a careful correction to account for the deleterious effects of the ground-based BiSON window function on the results. Results.From our full analysis we obtain a marginally significant result for the damping parameter, where the mean change is found to be weakest at ℓ=0.