I had a look at the file and tried to fix it. Firstly, I noticed that particles would all simultaneously fly out in a single cluster, then fall down forever.
We can turn off the gravity of the simulation here (I have disabled the checkbox, by default it is on):
Now, all particles will travel in a straight direction, without gravity. (There is an alternate method in the particle system settings if you only want to change that system’s physics, and not the world settings.)
I selected your particle emitter and changed the velocity for all input boxes to 0. This is what causes the particles to fly off.
Now, the particles remain spinning around the centre like a galaxy. The closer particles move faster, and the further ones move slower. You will have to alter the vortex so that it is centered and doesn’t move the particles away from where you want them.
I hope that is what you needed help with. It still is a little unclear. Just tell me if there is anything else that needs fixing.
I have a link to the modified .blend file: particlestest2.blend (5.8 MB)
(note: I have no idea why it has become 5mb in size)