The primary goal of the paper is to demonstrate that a circular jet of inviscid liquid, which issues from a nozzle at an angle to the gravitational field, can sustain a self-excited linear global mode. The mode is found for the flow that is locally convectively unstable at every point, i.e. has no region of local absolute instability. A simple experiment shows that the mode can evolve into a wave of finite amplitude, which is localized in space near the nozzle.

Section 2 of the paper summarizes some recent developments in the linear theory of stability of weakly inhomogeneous flows.