Plasma, the "Fourth State of Matter," was first identified in a Crookes tube, an experimental electrical discharge tube in which air is ionized by the application of a high voltage through a voltage coil, and it was described by Sir William Crookes, an English physicist, in 1879. It was first called "radiant matter”. However, Dr. Irving Langmuir, an American chemist and physicist, applied the word "Plasma" to ionized gas, in 1929. Plasma just happens to be the most common type of matter, comprising more than ninety-nine percent of matter in the visible universe in which impregnates the solar system, interstellar and intergalactic environments. Its temperatures and densities range from relatively cool and tenuous, to very hot and dense.
Plasma is defined by the existence of charged particles, both positive ions and negative electrons. The presence of a large number of charged particles makes the plasma electrically conductive so that it responds strongly to electromagnetic fields. Therefore, plasma has properties quite unlike those of solids, liquids, or gases and is considered a distinct state of matter. Plasma can be accelerated and steered by electric and magnetic fields, which allows it to be controlled and applied. Plasma research is yielding a greater understanding of the universe. It also provides many practical uses, such as; new manufacturing techniques, consumer products, the prospect of abundant energy, more efficient lighting, surface cleaning, waste removal, and many more application topics.
After the discovery of plasma, surgery without cutting and "bloodless scalpels" are now becoming a reality through cold plasmas that can inactivate bacteria through a combination of free radicals, charged particles, and UV, which work together to disrupt the integrity of bacterial cell membranes. In October, 2007, the first International Conference on Plasma Medicine was held to share advances in this cutting-edge field. It is