active region


Also found in: Acronyms.

active region

[′ak·tiv ′rē·jən]
(astronomy)
A localized, transient, nonuniform region on the sun's surface, penetrating well down into the lower chromosphere.
(electronics)
The region in which amplifying, rectifying, light emitting, or other dynamic action occurs in a semiconductor device.
References in periodicals archive ?
The differences persisted for at least a day prior to the first appearance of an active region.
In addition to the large and obvious sunspots, active regions contain a myriad of smaller magnetic structures surrounding the sunspots.
Contract notice: Executive / management of the active regions eider treene-care and southern north frisia.
It is believed that magnetic energy builds up in an active region as the magnetic field becomes distorted, for example by motions below the surface of the Sun dragging the magnetic fields around," explained Mason, whose research is partially funded by the UK's Science and Technology Facilities Council (STFC).
Within active regions on the sun--places that show intense magnetic activity--those areas that exhibit an S-shaped pattern in their X-ray emissions are the ones most likely to erupt.
Schubert's team focused on the active region of LEDs where the light is generated, and found that the region contained materials with mismatched polarization.
WASHINGTON (CyuHAN)- The Sun burst out with a curling spray of plasma from an active region just coming into view (Dec.
The entire length of pipeline is supposed to rest freely within a supporting "saddle" to permit some flexing or movement during tremors-a serious worry in this seismically active region of the world.
Thin layers of metallic phosphides containing indium, aluminum, and gallium make up the optically active region, which determines the wavelength of the resulting beam.
The Pfizer/Birkbeck team was able to show the structure of the active region of renin while it was occupied by prototype molecule designed by Pfizer chemists.
Minutes later, observers detected the first of six major, visible-light flares as the eruptive area -- now dubbed active region 6659 -- began migrating westward across the solar disk.
While the United States has historically been the most active region for deals, Europe and Asia will provide fertile grounds for buyers, given value considerations and a strong lack of mezzanine and secondary capital providers in these markets.

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