Lattice related brilliance increase at the ESRF

The ESRF brilliance is currently being increased by more than two orders of magnitude with respect to the original design target value of 1018 photons/sec/mm2/mrad2/0.1% relative bandwidth by acting on the stored beam current, the refinement of the insertion device technology and beam emittances. This paper reviews the lattice-related contribution to the on-going improvements of the initial performances in brilliance of the source: modifications in the tuning of the basic Chasman-Green lattice enabling the reduction of the horizontal emittance from the design 7 nm down to 4 nm, strategy to control the coupling below 1%, optimization of the beta functions in the insertion devices. This already brought a factor of 30 in brilliance. The potential for a further improvement in the brilliance by a factor of ten is described