Solar Flares

Geomagnetic storms, solar wind, and auroras, are mentioned very frequently recently. These are very interesting and very spectacular to learn about. However, what actually the cause of these phenomena? Solar flares. But what are solar flares?

Solar flares are gigantic bursts of energy from the Sun’s surface. The energy is the magnetic energy that is built up in the solar atmosphere. They release a significant amount of energy, about a sixth of the Sun’s energy lease per second. To the Sun’s scale, it is not much but to the Earth’s scale, energy release is equivalent to 100 millions ton of hydrogen bomb. A typical solar flare can release 10²⁷ ergs per second, equivalent to 10 millions time energy released in a volcano eruption. Solar flares eruption is associated with a Sun’s activity called coronal mass ejection (CME). CME is the process which the Sun ejected streams of very energetic particles. 

Even the flares are very powerful but the vast distance between us and the sun ensures that we will not receive a fireball from the Sun that threatens our planet. However, coronal mass ejection can travel and reach Earth and cause geomagnetic storms that interferes with radio communication, GPS, and satellites. Geomagnetic storms cause the Earth’s magnetic fields to change very quickly.

The Sun is current approaching its maximum in its 11 years cycle, which means that we will have solar flares more frequently. Earlier this month, the Sun erupted with one of the largest solar flares, categorized as X5.4. This solar flare is the second largest flare recorded.

The National Oceanic and Atmospheric Administration categorize the strength and sizes of solar flares in to classes, A, B, C, M, X. A is the weakest class which has a flux of smaller than 10^-7 watt/m². The strength increases 10 fold for each letter. As mentioned above, last week solar flare has X5.4 strength. So we also have X1, X2 and so on, up to X9. X2 is twice X1.  X3 is three times X1.

Sources:

http://en.wikipedia.org/wiki/Solar_flare

http://hesperia.gsfc.nasa.gov/sftheory/flare.htm

http://www.sciencedaily.com/releases/2012/03/120307185105.htm

http://www.sciencedaily.com/releases/2012/01/120125093821.htm