What direction of motion can a particles have in a Wilson chamber without a magnetic field?

The Wilson chamber is a simple device for determining the flight path of charged particles. The Wilson chamber is a vessel with a supersaturated vapor, therefore, when charged particles fly through it, they ionize the gas in the chamber (ionization occurs due to the fact that the particles are charged and the gas is neutral), and drops of liquid are formed on the ionized particles. In this case, neither gas nor vapor affects the motion of the particle.

If an a-particle flies through a Wilson chamber that is not in a magnetic field, its trajectory will be rectilinear, since no forces will deviate it from its original route.