feldabhängige

Feldabhängige describes a quantity whose value depends on a surrounding field. In physics, a field is a quantity defined at every point in space (and possibly time), such as electric, magnetic or gravitational fields. Feldabhängige Größen are those properties or observables that vary as the field varies with position or time.

In classical electromagnetism, many quantities are feldabhängig. For example, the force on a charged particle is proportional to the local electric field (F = q E), and the magnetic part of the Lorentz force depends on both the velocity of the particle and the local magnetic field (F = q v cross B). Potential energy and potential are also feldabhängige through the field values, with U(r) related to the electric potential V(r). Energy densities, such as the electric energy density w = 1/2 ε0 E^2, depend on the field strength at each point.

Other areas use feldabhängige properties as well. In optics, the refractive index can become feldabhängig through effects like the electro-optic (Pockels) and Kerr effects, where n changes as a function of an applied electric field. In gravitation, the gravitational potential φ determines the local potential energy mφ and influences the motion of bodies via the local gravitational field g.

Overall, the concept emphasizes that certain physical quantities do not have fixed values but are determined by the value of a field at the location of interest. The distinction between feldabhängige and field-free quantities helps describe how systems respond to environmental fields and enables modeling across classical and quantum contexts.