An Overview to Solar Flares
                     An Overview to 
Solar Flares
Introducti
on
A solar flare is a tremendous 
explosion on the Sun that 
happens when energy stored in 
'twisted' magnetic fields (usually 
above sunspots) is suddenly 
released.
Source: www.esa.int 2
Radiation across 
the 
Electromagnetic 
Spectrum
In a matter of just a few minutes 
they heat material to many 
millions of degrees and produce a 
burst of radiation across the 
electromagnetic spectrum, 
including from radio waves to x-
rays and gamma rays.
Source: www.esa.int 3
Classification 
of solar flares 
Scientists classify solar flares 
according to their brightness in 
the x-ray wavelengths. 
• X-class flares
• M-class flares
• C-class flares
Source: www.esa.int 4
X-class flares 
X-class flares are big; they are 
major events that can trigger 
radio blackouts around the whole 
world and long-lasting radiation 
storms in the upper atmosphere.
Source: www.esa.int 5
M-class flares
M-class flares are medium-sized; 
they generally cause brief radio 
blackouts that affect Earth's polar 
regions. Minor radiation storms 
sometimes follow an M-class flare.
Source: www.esa.int 6
C-class flares
Compared to X- and M-class 
events, C-class flares are small 
with few noticeable consequences 
here on Earth.
Source: www.esa.int 7
Solar Flares are 
brighter
Flares are brighter than the whole 
Sun in X-rays and in ultraviolet 
light. X-ray photons and high-
energy particles arrive 
immediately, but the main 
particle flux arrives a few days 
later.
Source: www.britannica.com 8
The Biggest 
flares
The biggest flares occur in 
association with large sunspots 
that have sharp magnetic 
gradients and large currents, 
which are the source of the flare 
energy.
Source: www.britannica.com 9
Filament 
Eruptions
There is a class of spotless flares 
associated with filament 
eruptions; they are large and 
sometimes produce coronal mass 
ejections but produce few high-
energy particles.
Source: www.britannica.com 10
Solar Flares 
vs. Coronal 
Mass 
Ejections 
Solar flares are different to 'coronal 
mass ejections' (CMEs), which were 
once thought to be initiated by solar 
flares. CMEs are huge bubbles of gas 
threaded with magnetic field lines 
that are ejected from the Sun over 
the course of several hours. 
Source: www.britannica.com 11