All About Space

What causes a solar flare?

- Marianna Korsos, research assistant at Aberystwyt­h University

Solar flares originate from highly complex and unstable strong magnetic fields that arc out over sunspots. Flares are driven by the so-called magnetic reconnecti­on process between oppositepo­larity magnetic fields. The magnetic field lines can meet, fuse and also break apart to create new connection­s.

During the reconnecti­on process, the released magnetic energy is converted into kinetic energy, thermal energy and particle accelerati­on that manifests in a burst of radiation across a wide range of the electromag­netic spectrum, from radio waves, through optical emission to X-rays and gamma rays.

Solar flares erupt outwards with speeds of up to a few million miles an hour, releasing massive amounts of energy. This can be equivalent to millions of nuclear bombs exploding simultaneo­usly. Flares are categorise­d according to their brightness in X-ray wavelength­s. The most powerful eruptions are X-class flares, which can trigger radio blackouts on Earth, and result in long-lasting radiation storms in Earth’s upper atmosphere. An M-class flare is about ten times weaker than an X-class one. These flares could cause brief radio blackouts that affect only Earth’s polar regions. The X- and M-class flares are often accompanie­d by coronal mass ejections (CMEs) that hurl enormous clouds of superheate­d plasma into space. Compared to X- and M-class events, C-, B- and A-classes are small, without any noticeable

consequenc­es on Earth.

 ??  ?? Right: Solar flares range in intensity depending on the solar cycle
Right: Solar flares range in intensity depending on the solar cycle
 ??  ??

Newspapers in English

Newspapers from United Kingdom