Solar flares are the sudden, rapid and intense variation in the brightness observed over the sun’s surface. It is interpreted as a large magnetic energy release that has built up in the solar atmosphere. Radiation is emitted across the entire electromagnetic spectrum., from radio waves at long wave length, through optical emission to x-rays and gamma rays at the short wavelength end. Generally, they are followed by Coronal Mass Ejection (CME) and the energy released is nearly equal to millions of 100 megaton hydrogen bombs exploding at the same time.
WHAT CAUSES SOLAR FLARE?
Several mechanisms are behind this radiation activity. Flares are thought to arise when strong magnetic fields undergo a process known as magnetic reconnection which releases massive amount of energy. A sudden blast accelerates charged particles some of which leave the sun while others are driven towards its visible surface. These accelerated particles are protons. When they collide with gasses in the sun’s atmosphere, the interaction creates a particle known as a pion which quickly decays into two gamma particles.
Sometimes there is coronal rain after the solar flare. Coronal rain occurs when plasma in the solar atmosphere cools and gets attracted by magnetic field on the Sun’s surface. Here is a short NASA video about the recent coronal rain in July 2012.
STAGES OF SOLAR FLARE
Precursor Stage: Magnetic energy is triggered.
Impulsive stage: Protons and Electrons are accelerated. Radiations also occur during this stage.
Decay Stage: Gradual build up and decay of soft x-rays.
CLASSIFICATION OF SOLAR FLARE
According to the peak flux:-
Hα spectral observations:-
Specialised scientific instruments are used to detect the radiation signatures emitted during a flare. The radio and optical emissions from these flares can be observed with telescopes on the Earth.
Optical Observations :
Solar Flare was first observed using optical observations on 1859. Flares which are not very bright can also be observed if a passband filter is used which centered at the wavelength of the radiations.
Solar flares are also observed using radio telescopes. It was first used by British radar operators during World War II.
Like the Hubble Space Telescope, these telescopes are sent to space, where they work at wavelengths below UV, which are completely absorbed by the atmosphere, and where flares may be very bright. Since the launch of Fermi Gamma-Ray Space telescope, studies are better than before and now we know how the sun produces gamma rays in solar flares.
EFFECTS OF SOLAR FLARE ON EARTH
It can cause radiation hazards to spacecraft, astronauts, and cosmonauts if they are in space. The particles of coronal mass ejection (CME) can impact Earth’s magnetosphere. Massive flares with CME can cause geomagnetic storms which can knock out electric power. Energetic particles of geomagnetic storms can cause aurora. The soft X-ray flux of X class flares increases the ionization of the upper atmosphere (ionosphere) , which interferes with short-wave radio communication and heats the outer atmosphere. It increases the drag on low orbiting satellites, leading to orbital decay. Hard x-rays can damage electronics of aircraft. Radiation are of major concern for manned mission to Mars. It can cause biochemical damage to astronauts.
A lot of people believe that solar flares might be the end of the world. We have nothing to fear as the radiation of these flares cannot penetrate the Earth’s atmosphere. Even as technology improves we keep on learning more and more about these flares. Flares might be an obstacle for a manned mission to Mars or other space missions but these obstacles have never stopped humanity from growing. Surely, we have a special ability of overcoming these obstacles and we continue to improve and make our lives better. Because of this, we have a powerful purpose – to inspire and enable change; to unlock creativity and enthusiasm. Providing the right products, tools and guidance; helping people transform ordinary spaces into authentic ones.
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