Upgrade of the neutral beam heating system on the TCV tokamak - second high energy neutral beam

The TCV tokamak continues to leverage its unique shaping capabilities, flexible heating systems and modern control system to provide a stepladder approach for extrapolations of experimental results from different ma-chines to ITER and DEMO. TCV's configurational flexibility has recently been enhanced by the installation of two heating neutral beams, new dual frequency gyrotrons, removable divertor gas baffles together with upgrades of its diagnostic infrastructure.Plasma regimes with high plasma pressure, a wider range of temperature ratios and significant fast-ion population are now attainable on TCV. A 1.3 MW/28 keV heating beam (NBI-1) has been operated on TCV from 2015 introducing the direct ion auxiliary heating. A second 1MW/50-60 keV high-energy neutral beam (NBI-2) has since been procured, manufactured and installed on TCV in July 2021. NBI-2 injected near anti-co -linearly to NBI-1 is designed to probe plasma physics issues of higher plasma density, fast ion plasma interactions with static and dynamic fields and plasma rotation. The higher NBI-2 energy greatly enhances the operational space for fast ion studies. NBI-2 commissioning is presently ongoing in parallel with TCV experiments using both NBIs.This paper summarises the experience with intensive use and improvements of the NBI-1, together with the status of NBI-2 commissioning.