#plasma $XPL Plasma: The most common state of matter in the universe

Plasma is the fourth state of matter, composed of free electrons, ions, and neutral particles, exhibiting electrical neutrality due to high ionization. It is widely present in the universe—at the core of the sun, in stellar atmospheres, interstellar space, and even in Earth's ionosphere and auroras, accounting for over 99% of visible matter.

Unlike solid, liquid, and gaseous states, plasma has unique properties: it is completely ionized at high temperatures, can conduct electricity, is strongly affected by electromagnetic fields, and has a strong absorption capability for electromagnetic waves. These characteristics make it widely used in industry and technology: welding and cutting using high-temperature plasma arcs; semiconductor manufacturing through plasma etching for precision chip processing; and controlled nuclear fusion using deuterium-tritium plasma as fuel, which holds promise for providing clean and limitless energy.

From cosmic bodies to everyday technology, plasma is both a product of natural evolution and a key to humanity's exploration of the future. It reminds us that the forms of the material world are far richer than we imagine, and science continues to unlock its hidden potential. @Plasma