Electromagnetic field

An electromagnetic field is a physical field that describes the behaviour of electrically charged particles and their interactions. It is a region of space where electric and magnetic forces are present. These fields are created by the presence or movement of electrically charged particles.

Electromagnetic field and particle physics

The electromagnetic field and the electromagnetic force are two different aspects of electromagnetism.

  • The electromagnetic force is one of the four fundamental forces of nature. It is the force that acts between charged particles.
  • The electromagnetic field is the field that mediates the electromagnetic force. It is a physical field that exists throughout space, and it is created by charged particles.
  • This means that the electromagnetic field is how the electromagnetic force is transmitted.
  • The electromagnetic field is a real physical field, just like the gravitational field.
  • When two charged particles such as electrons interact, they do so through the electromagnetic field.
  • The electromagnetic field is a two-component field. It has an electric component and a magnetic component. The electric field is created by charges, while the magnetic field is created by moving charges. The two fields are closely related, and they can be converted into each other.
  • The electromagnetic field is agitated by charged particles:
    • When a charged particle moves, it creates a disturbance in the electromagnetic field. This disturbance propagates through the field as a particle-wave, a photon.
    • Photons are particles of light and are responsible for the transmission of light energy.
    • The faster a charge moves, the stronger the electromagnetic field it creates. This is why magnets can attract and repel each other.
  • The electromagnetic field carries the force, in the form of the momentum and energy of a photon, between the particles, and it is the field that determines how the particles interact.
  • The electromagnetic field is present everywhere in the universe and manifests in many ways:
    • At the subatomic level, the electromagnetic field is responsible for the forces between charged particles.
    • At the atomic level, it is responsible for the bonding of atoms and molecules.
    • At the macroscopic level, it is responsible for light, electricity, and magnetism.
  • The electromagnetic field is a continuum, which means that there are no sharp boundaries between different regions of the field. It is a smooth, wave-like field that fills all of space. This means that the field at larger scales can influence the field at smaller scales, and vice versa. For example, the Earth’s magnetic field can influence the motion of electrons in atoms, which can lead to the emission of photons.
  • The electromagnetic field is a fundamental field of nature, and it does not require the presence of charged particles to exist. The field is always there, even if it is not being disturbed.

An electromagnetic field can be thought of as a single more complete object than its component electric and magnetic field. It propagates through space in the form of bundles of energy called photons which are configured as electromagnetic waves, the force carriers of radiant energy (electromagnetic radiation).

  • An electromagnetic field results from the coupling of an electric and magnetic field.
  • When an electromagnetic field experiences a change in voltage or current its reconfiguration into an electromagnetic wave can be described in terms of wavelength, frequency and energy.
  • An electromagnetic wave can be thought to come into existence when a static electric field experiences a change in voltage or a static magnetic field experiences a change in current producing radiating oscillations of electromagnetic energy that propagate through space.
  • The difference between an electromagnetic field and an electromagnetic wave is that the wave has a non-zero frequency component which is the source of the energy it transports.
  • Electromagnetic radiation is essentially the result of an oscillating electromagnetic field propagating through space.