If the vector field F (m) is the gradient of a certain scalar function f (m), then it is called a potential function of F (m) f (m), and f (m) is called a potential field

If the vector field F (m) is the gradient of a certain scalar function f (m), then it is called a potential function of F (m) f (m), and f (m) is called a potential field

The gradient F of the quantity field F is the normal vector of the isosurface of F. the value of F is equal to the change rate of the value of F with distance in the direction of the normal vector