particles stream

Hi everyone
I’m dealing with particles, and there is and Particle effect that I’m trying to do and I can’t find the way.

I’ve a particle stream, but, I want that produce and Arc. Do the particle stream it’s fine, but to produce the arc (like a water arc for example… ) I can’t
I’ve thought that if I add a gravity and I apply a huge velocity, it works… but doens’t I thougt as well add and animation to the trigger in the gravity, but… doesnt’ work either.
Also… Any idea?