The term plasma refers to a condition of matter sufficiently different from solids, liquids, and gases to have earned the description, "the fourth state of matter. " The state develops when a gas is heated to such a high temperature that all atoms in the gas are ionized. In this state, matter consists of positively charged ions and electrons in apparently random motion. The name plasma was given to this state by the American chemist Irving Langmuir in 1920.

The study of plasma-like materials actually goes as far back as the 1830s when the English physicist, Michael Faraday, passed electrical discharges through gases at low pressures. Faraday's research was extended and expanded by William Crookes in the 1870s. Crookes was apparently the first scientist to suggest that the ionized gas within his glass tubes might be a fourth state of matter.

Plasma research during the 1920s and 1930s was largely...