Rotation Object
Basic Coord. Object FalloffRotation Object
Rotation imposes a velocity vector in the XY plane of the modifier that is always tangential to a circle whose radius connects the particle and the modifier’s Z axis. This rotation occurs around. The Z axis of the Rotation modifier.
For an interesting effect, place the modifier with its Z axis parallel to the direction of the starting point of the particles. This will create a spiral-shaped helical movement.