| Supernova remnants provide kinetic energy, heavy elements, and accelerated particles into the space. In other words, supernova remnants make the diversity of our Universe. Plasmas in supernova remnants heated by shocks show us critical information such as the time scale of collisionless shock heating, abundance pattern of each remnant, and plasma evolution, and so on. On the other hand, their plasma is one of the most complicated one due to the nonequilibrium states both in ionizing and recombining, strongly different abundance pattern position to position, and so on. In this paper, we will discuss how X-ray spectroscopy promoted our understandings of supernova remnants. |