Divergence
A scalar differential operator measuring the net outward flux density of a vector field from an infinitesimal volume around a given point.
Governing formula
div F = ∇ · F = (∂F_x/∂x) + (∂F_y/∂y) + (∂F_z/∂z)
SI unit
[Vector Field Unit] / m
In depth
Positive divergence indicates a local net source where field lines diverge; negative divergence indicates a local net sink; zero divergence (∇ · F = 0) defines a solenoidal, incompressible field.
Examples in the real world
Gauss's law ∇ · E = ρ / ε₀ indicating electric charges act as sources and sinks of electric fields.