Spherical Field
The spherical field is used to push particles away from a spherical volume. It is useful for shaping the form and integrating the form with other graphic elements. For example, it can be used to push particles away from an area where a logo is placed. There are two fields and they are processed in order: first Sphere 1 and then Sphere 2.
Strength
Defines the power of the field. When set to a negative value, the field pulls particles toward the center rather than pushing them away.

Zero | Positive | Negative

Position X, Y, and Z
Positions the center of the sphere in 3D space.
Radius
Defines the size of the sphere.
Feather
Defines the softness of the sphere.
Visualize Field
When this checkbox is on, a visual representation of the field is displayed.