sädekenttiä

Sädekenttiä, often translated as "radial fields" or "ray fields" in English, is a concept in theoretical physics and mathematics that describes a specific type of vector field. A vector field assigns a vector to each point in space. In a sädekenttä, these vectors consistently point directly away from or towards a central point. This means that the direction of the vector at any given point is purely radial, meaning it lies along the line connecting that point to the origin.

The magnitude of the vectors in a sädekenttä can vary depending on the distance from the central point. For example, a common type of sädekenttä has a magnitude that decreases with the square of the distance from the origin, a characteristic seen in gravitational and electrostatic fields. Conversely, the magnitude could increase or remain constant, depending on the specific mathematical definition being used.

Sädekenttiä are important in various areas of physics. They are fundamental to understanding central forces, such as gravity and the electrostatic force between point charges. In fluid dynamics, a radial velocity field might describe a source or sink of fluid emanating from or flowing into a central point. Mathematically, the divergence of a pure sädekenttä is zero everywhere except at the origin, where it can be a Dirac delta function, representing a source or sink. The curl of a sädekenttä is always zero, indicating that it is an irrotational field.