Update on Nonlinear Collimation Schemes for the LHC

In this paper we review the status of the studies on nonlinear collimation schemes for the LHC. Concretely we describe the design of a nonlinear optics for betatron cleaning in IR7. The aim is to investigate alternative nonlinear collimation systems to reduce the collimator-induced impedance that may limit the beam intensity towards the LHC luminosity upgrade. The performance of the LHC nonlinear collimation system is studied by means of tracking simulations and compared with the present LHC system. Furthermore, the advantages and possible limitations of such nonlinear collimation scheme are discussed.