Attractor

An attractor is a force that attracts particles to a certain position in space. It could be a static position, or it could another particle that aces as center of the attraction. The attractor usually has a falloff so it attracts closer particles more than the ones far away.

If you give an attractor a negative force, it becomes the opposite, a repeller. It repels particles, pushes them away from the point.

Some examples of effects that can be created by an attractor: