different between radiation vs radiansphere

English

Etymology

Borrowed from Latin radiatio, radiationis.Morphologically radiate +? -ion

Pronunciation

• IPA^(key): /??e?.di.?e?.??n/
• (some US dialects) IPA^(key): /?a?.di.?a?.??n/

Noun

radiation (countable and uncountable, plural radiations)

1. The shooting forth of anything from a point or surface, like diverging rays of light.

   heat radiation

   • 2016, Donald R. Prothero, The Princeton Field Guide to Prehistoric Mammals (page 136)

     The second [canid group] is the radiation of dogs in South America that began when the first canids arrived about 3 Ma, after crossing the Panama land bridge (Fig. 5.4).

2. The process of radiating waves or particles.
3. The transfer of energy via radiation (as opposed to convection or conduction).
4. Radioactive energy.

Related terms

• radiate

Derived terms

Translations

See also

• nucleomitophobia

Anagrams

• antiradio

French

Etymology

Borrowed from Latin radiatio, radiationem.

Pronunciation

• IPA^(key): /?a.dja.sj??/

Noun

radiation f (plural radiations)

1. radiation (all meaning)

Related terms

• radier

Further reading

• “radiation” in Trésor de la langue française informatisé (The Digitized Treasury of the French Language).

English

Etymology

radian +? sphere

Noun

radiansphere (plural radianspheres)

1. A spherical region of radius ?/2? around a small dipole electromagnetic antenna. This is the distance at which the induction and radiation terms are equal in magnitude. Inside, the induction terms dominate. In radio antenna theory the radiansphere is a convenient definition for the boundary between near-field and far-field regions.
   • 1959, Harold Alden Wheeler, "The Radiansphere around a Small Antenna", Proceedings of the IRE, August, Volume 47, Issue 8, page 1325

     "The "radiansphere" is the boundary between the near field and the far field of a small antenna. Its radius is one radianlength (?/2?), at which distance the three terms of the field are equal in magnitude. A "small" antenna is one somewhat smaller than the radiansphere, but it has a "sphere of influence" occupying the radiansphere.