A Solar Storm can be refered to different situations:
- Solar flare, a large explosion in the Sun's atmosphere
- Coronal mass ejection (CME), a massive burst of solar wind, sometimes associated with solar flares
- Geomagnetic storm, the interaction of the Sun's outburst with Earth's magnetic field
A solar flare is a sudden brightening observed over the Sun surface or the solar limb, which is interpreted as a large energy release of up to 6 × 1025 joules of energy (about a sixth of the total energy output of the Sun each second) or 160,000,000,000 megatons of TNT equivalent. The flare ejects clouds of electrons, ions, and atoms through the corona into space. These clouds typically reach Earth a day or two after the event.
Solar flares affect all layers of the solar atmosphere (photosphere, chromosphere, and corona), when the medium plasma is heated to tens of millions of kelvins and electrons, protons, and heavier ions are accelerated to near the speed of light. They produce radiation across the electromagnetic spectrum at all wavelengths, from radio waves to gamma rays, although most of the energy goes to frequencies outside the visual range and for this reason the majority of the flares are not visible to the naked eye and must be observed with special instruments. 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. The same energy releases may produce coronal mass ejections (CME), although the relation between CMEs and flares is still not well established.
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.
Coronal Mass Ejection
Coronal mass ejections release huge quantities of matter and electromagnetic radiation into space above the sun's surface, either near the corona (sometimes called a solar prominence) or farther into the planet system or beyond (interplanetary CME). The ejected material is a plasma consisting primarily of electrons and protons, but may contain small quantities of heavier elements such as helium, oxygen, and even iron. It is associated with enormous changes and disturbances in the coronal magnetic field.
A geomagnetic storm is caused by a solar wind shock wave and/or cloud of magnetic field which interacts with the Earth's magnetic field. The increase in the solar wind pressure initially compresses the magnetosphere and the solar wind magnetic field will interact with the Earth’s magnetic field and transfer an increased amount of energy into the magnetosphere. Both interactions cause an increase in movement of plasma through the magnetosphere (driven by increased electric fields inside the magnetosphere) and an increase in electric current in the magnetosphere and ionosphere. During the main phase of a geomagnetic storm, electric current in the magnetosphere create magnetic force which pushes out the boundary between the magnetosphere and the solar wind.
The solar storms have effects on:
- Radio communications fadeouts;
- Auroras Borealis and Australis;
- Disruption in power lines;
- Disruption in radio transmission;
- Geomagnetic storms;
- Ionospheric storms;
- Radiation hazards in astronauts.
A solar storm in March 22:
"For the three day period, March 8th through 10th, the thermosphere absorbed 26 billion kWh of energy. Infrared radiation from CO2 and NO, the two most efficient coolants in the thermosphere, re-radiated 95% of that total back into space."
|A surge of infrared radiation from nitric oxide molecules on March 8-10, 2012, signals the biggest upper-atmospheric heating event in seven years. Credit: SABER/TIMED. See also the CO2 data.|