The variation in the strength of low-l solar p-modes - 1981-92

The acoustic eigenmodes of the Sun are a well-recognized probe of the structure of the solar interior. We report here on a measurement of the strength of the low-l p-mode oscillations throughout a solar cycle. There is an increase of 35 +/- 5 per cent in the strength of the modes from solar maximum to solar minimum, consistent for all the l-values measured. The observations were made with the Birmingham Solar Oscillations Network ('BISON').