|Evolution of the January 23, 2012 solar flare. Images, from left to right,|
taken at 3:27, 3:42, and 4:13 UT. NASA Solar Dynamics Observatory
What is the difference between a solar flare and a coronal mass ejection? A solar flare is an intense burst of radiation from a sunspot as magnetic energy is released in an explosive event. It releases light at almost every wavelength of the spectrum. A coronal mass ejection is mass released during a flare, primarily gas, often billions of tons. CME's are sometimes associated with flares, but can also occur independently of a flare.
How are solar flares classified?
Solar flares are classified on a logarithmic scale (similar to the Richter magnitude scale), with each class having a peak flux ten times greater than the preceding one. The flux is measured in watts per square meter (W/m**2) in a particular wavelength range (100-800 picometer X-rays) near the Earth, as measured by GEOS spacecraft. Within each class there are 9 sub-categories, each being twice as big as the previous one. The classes are, in increasing order, A,B,C,M, and X. The flare discussed here was rated as a M8.7, just slightly below the most intense X category.
How is the effect of a flare on the earth classified?
A solar flare and CME can cause a geomagnetic storm on the earth, a disruption of our magnetosphere.
Here's a link to the classification of the effects of geomagnetic storms on earth.
Here's a link to a longer explanation.
Here, here, and here are previous posts on this blog that might be of interest.