  It is speculated that the accretion of material onto young protostars is
episodic. We present a computational method to include the effects of episodic
accretion in radiation hydrodynamic simulations of star formation. We find that
during accretion events protostars are "switched on", heating and stabilising
the discs around them. However, these events typically last only a few hundred
years, whereas the intervals in between them may last for a few thousand years.
During these intervals the protostars are effectively "switched off", allowing
gravitational instabilities to develop in their discs and induce fragmentation.
Thus, episodic accretion promotes disc frag- mentation, enabling the formation
of low-mass stars, brown dwarfs and planetary-mass objects. The frequency and
the duration of episodic accretion events may be responsible for the low-mass
end of the IMF, i.e. for more than 60% of all stars.
