Plasma is an appellation for a kind of unstable aggregation state of high energy level. Through the input of energy, the material is transformed from solid and liquid to gas. Additional energy is injected into the gas through the discharge action, and then the plasma state is produced.
The input of the energy allows electrons to break away from their atomic orbitals and can break the chemical bonds to form free electrons, ions, and molecules. The result of this process is regarded as the fourth state of material existence except for solid, liquid and gas states.