Related topics: sun

Heating the solar corona

The hot outer layer of the sun, the corona, has a temperature of over a million degrees Kelvin, much more than the surface temperature of the Sun which is only about 5500 degrees Kelvin. Moreover, the corona is very active ...

Solar physics with the Square Kilometre Array

Although solar physics is one of the most mature branches of astrophysics, the sun confronts researchers with a large number of outstanding fundamental problems. These problems include the determination of the structure ...

Scientists reproduce the dynamics behind astrophysical shocks

High-energy shock waves driven by solar flares and coronal mass ejections of plasma from the sun erupt throughout the solar system, unleashing magnetic space storms that can damage satellites, disrupt cell phone service and ...

Solar weather has real, material effects on Earth

On Sep. 1, 1859, solar astronomer Richard Carrington witnessed sunspots that suddenly and briefly flashed brightly before they disappeared. Just before dawn the next day, auroras erupted over most of the Earth, reaching as ...

The sun may have a dual personality, simulations suggest

Researchers at CU Boulder have discovered hints that humanity's favorite star may have a dual personality, with intriguing discrepancies in its magnetic fields that could hold clues to the sun's own "internal clock."

A new method for 3-D reconstructions of eruptive events on sun

An international team of scientists led by Skoltech professor Tatiana Podladchikova developed a new 3-D method for reconstructing space weather phenomena, in particular, shock waves produced by the Sun's energy outbursts. ...

Giant stellar eruption detected for the first time

A group of researchers has identified and characterized for the first time in a complete way a powerful eruption in the atmosphere of the active star HR 9024, marked by an intense flash of X-rays followed by the emission ...

page 1 from 23

Solar flare

A solar flare is a big explosion in the Sun's atmosphere that can release as much as 6 × 1025 joules of energy. The term is also used to refer to similar phenomena in other stars, where the more accurate term stellar flare applies.

Solar flares affect all layers of the solar atmosphere (photosphere, corona, and chromosphere), heating plasma to tens of millions of kelvins and accelerating electrons, protons, and heavier ions to near the speed of light. They produce radiation across the electromagnetic spectrum at all wavelengths, from radio waves to gamma rays. Most flares occur in active regions around sunspots, where intense magnetic fields penetrate the photosphere to link the corona to the solar interior. Flares are powered by the sudden (timescales of minutes to tens of minutes) release of magnetic energy stored in the corona. If a solar flare is exceptionally powerful, it can cause coronal mass ejections.

X-rays and UV radiation emitted by solar flares can affect Earth's ionosphere and disrupt long-range radio communications. Direct radio emission at decimetric wavelengths may disturb operation of radars and other devices operating at these frequencies.

Solar flares were first observed on the Sun by Richard Christopher Carrington and independently by Richard Hodgson in 1859 as localized visible brightenings of small areas within a sunspot group. Stellar flares have also been observed on a variety of other stars.

The frequency of occurrence of solar flares varies, from several per day when the Sun is particularly "active" to less than one each week when the Sun is "quiet". Large flares are less frequent than smaller ones. Solar activity varies with an 11-year cycle (the solar cycle). At the peak of the cycle there are typically more sunspots on the Sun, and hence more solar flares.

This text uses material from Wikipedia, licensed under CC BY-SA