Collective Beam Instabilities Caused by RF Cavities in Tristan

Summarized are the works done at KEK to study the collective beam instabilities caused by the RF cavities in TRISTAN. The works include the higher-order mode loss, the longitudinal and transverse coupled-bunch instabilities and the single bunch fast instabilities for longitudinal and transverse motions. A design aim of 4 mA/bunch and two bunches per beam can be achieved when feedback systems for longitudinal and transverse dipole oscillations are used. The other cures such as the higher-harmonic cavities, the wigglers, the couplers and the change of radiation damping partititon numbers are also desirable.