HE-LHC: requirements from beam vacuum

First thoughts on the design of the beam vacuum system for the High Energy LHC (HE-LHC) are given with a particular focus on the impact of the synchrotron radiation. In the HE-LHC, the vacuum dynamic effects induced by the circulating beams are expected to be as compared to the LHC. These effects will be reviewed and first thoughts on how to avoid or mitigate their effects are discussed.