An Etymological Dictionary of Astronomy and Astrophysics
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A magnetic field whose lines of force are oriented along a particular direction or by a particular manner (axially, vertically; randomly, properly, etc.)

→ aligned; → magnetic field.

In the → solar dynamo model, a magnetic field that points from east to west or vice-versa.

→ azimuthal; → magnetic; → field.

A → magnetic field whose lines of force (→ line of force) run around the perimeter of the magnet.

→ circular; → magnetic; → field.

Relative to or characterized by → diamagnetism.

→ diamagnetism.

A → magnetic field produced by a system possessing a net magnetic → dipole moment.

→ dipolar; → magnetic; → field.

Of or pertaining to electromagnetism or electromagnetic fields.

→ electro- + → magnetic

An → electromagnetic signal associated with the location on the sky and the time of a → gravitational wave event. The electromagnetic signal is predicted by models to be associated with the → merger of a → compact binary star system composed of two → neutron stars (NS) or a neutron star and a → black hole (BH). Accordingly, the gravitational waves are accompanied by a short-duration → gamma-ray burst (GRB) powered by the → accretion of material that remains in a → centrifugally supported → torus around the BH following the merger. NS-NS/BH-NS mergers are also predicted to be accompanied by a more isotropic counterpart, commonly known as a → kilonova. Kilonovae are day to week-long thermal, → supernova-like → transients, and are powered by the → radioactive decay of heavy, neutron-rich elements synthesized by the → r-process in the expanding merger ejecta (Li and Paczynski 1998). The first detection of an electromagnetic counterpart to gravitational waves belongs to → GW170817.

→ electromagnetic; → counterpart.

Same as → fine-structure constant.

→ electromagnetic; → coupling; → constant.

A region of space consisting of coupled electric and magnetic lines of force at each point, generated by time-varying currents and accelerated charges.

→ electromagnetic; → field.

The fundamental force that is associated with electric and magnetic fields. One of the four fundamental forces of nature, it is carried by photons.

→ electromagnetic; → force.

The production of an → electromotive force in a circuit caused by a variation in the magnetic flux through the circuit. If this variation is produced by a change in the current flowing in the circuit itself, it is called → self-induction. If due to the variation in a current in some other circuit, it is called mutual induction. See also → Faraday's law of induction.

→ electromagnetic; → induction.

The combination of both → electric scalar potential and → magnetic vector potential.

→ electromagnetic; → potential.

Radiation propagating in the form of an advancing wave in electric and magnetic fields. It includes radio waves, infrared, visible light, ultraviolet, X-rays, and gamma rays.

→ electromagnetic; → radiation.

Information transmitted by means of a modulated current or an electromagnetic wave and received by telephone, radio, television, etc.

→ electromagnetic; → signal.

The range of frequencies over which electromagnetic waves are propagated. → electromagnetic radiation.

→ electromagnetic; → spectrum.

The description of combined electric and magnetic fields mainly by → Maxwell's equations. Same as → electromagnetism.

→ electromagnetic; → theory.

The theory describing light as a wave phenomenon resulting from the combination of two electric and magnetic fields vibrating transversely and mutually at right angles. → electromagnetic radiation; → electromagnetic wave; → Maxwell's equations.

→ electromagnetic; → theory; → light.

A wave produced by oscillation or acceleration of an electric charge. → electromagnetic radiation.

→ electromagnetic; → wave.

Relative to or characterized by → ferromagnetism.

→ ferro-; → magnetic.

The condition in a plasma when the → Lorentz force is zero, that is when the electric current flows along the magnetic field. Force-free magnetic fields are encountered in astrophysical plasmas with negligible gas pressure. The solar corona is the best available example of such fields in action in a plasma.

→ force; → free; → magnetic; → field.