Aug 11, 2014
Soft X-ray Emissions from Charge Exchange in the Heliosphere
The solar wind originates in the sun’s corona, the hottest part of its atmosphere, so its atoms have been ionized, stripped of many of their electrons. When these particles collide with a neutral atom, one of its electrons often jumps to the solar wind ion. Once captured, the electron briefly remains in an excited state, then emits a soft X-ray and settles down at a lower energy. X-rays with photon energies above 5–10 keV (below 0.2–0.1 nm wavelength) are called hard X-rays, while those with lower energy are called soft X-rays.
Credit: NASA’s Goddard Space Flight Center
