  We have used very high-cadence (sub-minute) observations of the solar mean
magnetic field (SMMF) from the Birmingham Solar Oscillations Network (BiSON) to
investigate the morphology of the SMMF. The observations span a period from
1992--2012, and the high-cadence observations allowed the exploration of the
power spectrum up to frequencies in the mHz range. The power spectrum contains
several broad peaks from a rotationally-modulated (RM) component, whose
linewidths allowed us to measure, for the first time, the lifetime of the RM
source. There is an additional broadband, background component in the power
spectrum which we have shown is an artefact of power aliasing due to the low
fill of the data. The sidereal rotation period of the RM component was measured
as $25.23 \pm 0.11$ days and suggests that the signal is sensitive to a
time-averaged latitude of $\sim 12^{\circ}$. We have also shown the RM lifetime
to be $139.6 \pm 18.5$ days. This provides evidence to suggest the RM component
of the SMMF is connected to magnetic flux concentrations (MFCs) and active
regions (ARs) of magnetic flux, based both on its lifetime and location on the
solar disc.
