#plasma $XPL Plasma, the fourth state of matter, forms when a gas is superheated—often to tens of thousands of degrees—causing atoms to lose electrons and create a mix of ions and free electrons. This ionized, electrically conductive fluid conducts electricity, responds to magnetic fields, and emits light, making it the substance of stars, lightning, and neon signs. On Earth, plasma appears in fusion research, fluorescent lamps, and cutting torches. Unlike solids, liquids, or gases, plasma’s particles move independently, allowing unique behaviors like filamentation and wave propagation. Scientists study plasma to advance clean fusion energy, space weather forecasting, and advanced materials processing across physics and engineering disciplines worldwide.