This paper presents the nonlinear dynamics of laser cooled and trapped
cesium atoms placed inside an optical cavity and interacting with a p
robe light beam slightly detuned from the 6S(1/2)F=4 to 6P(3/2)F=5 tra
nsition. The system exhibits very strong bistability and instabilities
. The origin of the latter is found to be a competition between optica
l pumping and nonlinearities due to saturation of the optical transiti
on.