# Spectra of electromagnetic radiation emitted during solar flare

During solar flare, electromagnetic energy is released at a wide range of wavelengths but the most dominating are x-rays and extreme ultraviolet rays. Why is that intensity of these wavelengths is greatest?

• – Aaron Dec 6 '14 at 19:56

The plasma heats up, increases its pressure and it expands to fill the overlying magnetic structures - a.k.a. chromospheric evaporation. This hot plasma radiates and because it is at temperatures between $10^{5}$ and $10^7$ K, most of that radiation is emitted at EUV and X-ray wavelengths in free-free and transitions in highly ionised species.