We carry out three dimensional radiation hydrodynamical simulations of
gravitationally unstable discs using to explore the movement of mass in a disc
following its fragmentation. Compared to a more quiescent state before it
fragments, the radial velocity of the gas increases by up to a factor of ~2-3
after fragmentation. While the mass movement occurs both inwards and outwards,
the inwards motion can cause the inner spirals to be sufficiently dense that
they may become unstable and potentially fragment. Consequently, the dynamical
behaviour of fragmented discs may cause subsequent fragmentation at smaller
radii after an initial fragment has formed in the outer disc.Comment: Submitted to the conference proceedings of: Instabilities and
Structures in Proto-Planetary Disks. 5 pages; 4 figure
