Abstract :
In the CERN linear accelerator, intensities above 125 mA have been accelerated. For very big, present and future AG synchrotrons, however, there is a need for injectors giving 200 mA or more. At this intensity level, very strong longitudinal space charge effects occur which limit the phase stability in linacs and which also have been shown to prevent efficient bunching with conventional bunchers. Proposals are given to raise the limit of these effects to about half an ampere where beam loading compensation may become difficult. For a better prediction of the performances, several studies are still to be made and various methods are outlined; a few difficult points may, however, require further effort, especially if still higher intensities and extreme performances are needed.
