Flare

flare

A space weather term for a sudden eruption of energy in the solar atmosphere lasting from minutes to hours from which radiation and particles are emitted. Flares are officially measured and classified based on peak X-ray flux from 1-minute-averaged GOES X-ray Sensor (XRS) observations in the 1–8-angstrom passband. Classification generally begins at the "B" level (>0.000 000 1 W m⁻²) and increases by an order of 10 with each subsequent level to "C" flares, "M" flares, and "X" flares. Flare levels of B, C, and M are assigned multiplicative factors (1–9), which are appended to the letter (e.g., M4); flare levels of X are appended with a multiplicative factor from 1 to 20 (anything above 20 is estimated).

Space Weather Prediction Center, 2018: Solar flares (Radio blackouts). Accessed 14 August 2018. Available at https://www.swpc.noaa.gov/phenomena/solar-flares-radio-blackouts.

Term edited 14 August 2018.

(Or x-radiation, Röntgen ray.) Electromagnetic radiation with wavelengths shorter than that of ultraviolet radiation and greater than that of gamma radiation.
Discovered accidentally by Röntgen in 1895. The primary mechanism for the production of x- rays is deceleration of a rapidly moving charge upon interaction with matter (bremsstrahlung). The x-ray spectrum from an x-ray tube consists of this continuous spectrum on which are superimposed narrow bands (characteristic radiation) that are a consequence of transitions between electronic energy levels of atoms. No sharp boundary exists between x- and ultraviolet radiation nor between x- and gamma radiation, although the latter term is usually restricted to radiation resulting from transitions between nuclear energy levels.
Boorse, H. A., and L. Motz 1966. The World of the Atom. Vol. 1, . 385–401.

See numerical weather prediction, climate prediction;