An Etymological Dictionary of Astronomy and Astrophysics
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A → scalar field supposed to be responsible for the genesis of → inertial mass. According to the → standard model of → particle physics, the Higgs field appeared 10^-36 to 10^-12 seconds after the → Big Bang, during the → electroweak epoch, when the temperature dropped below a critical threshold. The Higgs field permeates all space, and through its interaction with the fundamental particles it provides those particles with a mass. Any particle that does not interact with the Higgs field, such as the → photon, will be mass-less.

→ Higgs boson; → field.

An image of a small region in the constellation → Ursa Major, based on the results of a series of observations by the → Hubble Space Telescope. The image was assembled from 342 separate exposures taken over ten consecutive days between December 18 and December 28, 1995. It covers an area 144 arcseconds across.

→ Hubble; → deep; → field.

An electric field created by the variation of a magnetic field. The induced electric field lines are usually perpendicular to the changing magnetic field that produces them.

→ induced; → electric; → field.

A component of an electromagnetic field which is the region close to the source (an antenna) where steady-state magnetic and electrostatic forces can be detected. → radiation field.

→ induction; → field.

A hypothetical → scalar field that provides a theoretical basis for → inflation in the early → Big Bang history of the → Universe. The inflaton field would fill space with the same energy at every point. In general, the scalar field can vary with time and space, though to a first approximation everywhere in the Universe will have the same value at any time. The field has a particle associated with it, called → inflaton, just as the → electromagnetic field is associated with the → photon. The inflaton field is characterized also by a → negative pressure that would yield a tremendous → repulsive gravity during a brief lapse of time. In the earliest moments of the Universe, space is uniformly filled with an inflaton field, whose value places it higher up on its → potential energy curve. The inflaton's → potential energy would drop in a tiny fraction of a second, on the order of 10^-35 seconds. And yet, during that brief instant, space would expand by a colossal factor, of at least 10³⁰.

→ inflaton; → field.

A technique in spectroscopy for recording a spectrum from each point of an extended object. The field of view image is divided into a multitude of small components using different methods, e.g. lenslet arrays, fiber bundles, or image slicers. From each component a spectrum is extracted or an image is reconstructed at a particular wavelength.

→ integral; → field; → spectroscopy.

The magnetic field that is carried along with the solar wind and fills the solar system space. It is wound into a spiral structure by the rotation of the Sun. At the Earth's distance from the Sun, it has a strength of about 5 x 10^-5 gauss.

→ interplanetary; → magnetic; → field.

A large-scale, weak magnetic field, with an estimated strength of about 1 to 5 microgauss, that pervades the disk of the Milky Way Galaxy and controls the alignment of interstellar dust grains.

→ interstellar; → magnetic; → field.

A global ionizing radiation in the → interstellar medium provided by various sources all together.

→ interstellar; → radiation; → field.

1) A → magnetic field whose lines of force (→ line of force) run parallel to the long axis of the → magnet. Longitudinal magnetization of a component can be accomplished using the longitudinal field set up by a → coil or → solenoid. It can also be accomplished using permanent magnets or electromagnets.
2) In → stellar magnetic field observations, the magnetic field along the → line of sight.

→ longitudinal; → magnetic; → field.

A field of force that is generated by electric currents, or, equivalently, a region in which magnetic forces can be observed.

→ magnetic; → field.

An imaginary line used for representing the strength and direction of a magnetic field. Charged particles move freely along magnetic field lines, but are inhibited by the magnetic force from moving across field lines.

→ magnetic; → field; → line.

Same as → magnetic intensity.

→ magnetic; → field; → intensity.

In the → solar dynamo model, a magnetic field that points from the north to south or south to north.

→ meridional; → magnetic; → field.

In the context of solar physics, a → magnetic field line when it crosses the solar surface only once, i.e., when it goes from surface to infinity. This is the case at a sufficiently large scale in → coronal holes. This is mostly not the case in → active regions.

→ open; → magnetic; → field; → line.

1) In → protoplanetary disk models, the magnetic field whose large-scale lines of force depart away from the → accretion disk, in the direction of the rotation axis.
2) In a → tokamak, the magnetic field produced by a current flowing in the → plasma vertically to the toroid plane. → toroidal magnetic field.

→ pole; → -oid; → magnetic field.

A field that has a → potential. A continuous → vector fieldA in a domain D is a potential field in D if and only if its → work around every closed curve C contained in D is zero: ∫A.ds = 0. Examples include the → gravitational field and the → electrostatic field.

→ potential; → field.

The quantum mechanical theory based on the assumption that the interactions between particles and fields are mediated by messenger particles. Accordingly, particles are → quanta of a field, just s photons are quanta of light. All fields display a granular structure in interaction. QFT is the framework in which quantum mechanics and → special relativity are successfully reconciled (→ Dirac equation). It forms the basis of today's particle physics.

→ quantum; → field; → theory.

1) The portion of an → electromagnetic field outside the → induction field where there is a power flow of both → magnetic and → electric components in a well-defined relationship.
2) → interstellar radiation field

→ radiation; → field.

The magnetic field left in an iron core after excitation has been removed.

→ residual; → field.