  The transport of particles via intermittent filamentary structures in the
private flux region of plasmas in the MAST tokamak has been investigated using
a fast framing camera recording visible light emission from the volume of the
lower divertor, as well as Langmuir probes and IR thermography monitoring
particle and power fluxes to plasma-facing surfaces in the divertor. The
visible camera data suggests that, in the divertor volume, fluctuations in
light emission above the X-point are strongest in the scrape-off layer (SOL).
Conversely, in the region below the X-point, it is found that these
fluctuations are strongest in the private flux region (PFR) of the inner
divertor leg. Detailed analysis of the appearance of these filaments in the
camera data suggests that they are approximately circular, around 1-2cm in
diameter. The most probable toroidal mode number is between 2 and 3. These
filaments eject plasma deeper into the private flux region, sometimes by the
production of secondary filaments, moving at a speed of 0.5-1.0km/s. Probe
measurements at the inner divertor target suggest that the fluctuations in the
particle flux to the inner target are strongest in the private flux region, and
that the amplitude and distribution of these fluctuations are insensitive to
the electron density of the core plasma, auxiliary heating and whether the
plasma is single-null or double-null. It is found that the e-folding width of
the time-average particle flux in the PFR decreases with increasing plasma
current, but the fluctuations are unchanged. At the outer divertor target, the
fluctuations in particle and power fluxes are strongest in the SOL.
