Equations of Plasma Physics

Abstract

Notes by Stephen (haohundro Pia •••• A plasma is a gas of charged particles under conditions where collective electromagnetic interactions dominate over interactions between individual particles. Plasmas have been called the fourth state of matter [1 J. As one adds heat to a solid, it undergoes a phase transition (melting) to become a liquid. More heat causes the liquid to boil into a gas. Adding still more energy causes the gas to ionize (i.e. some of the negative electrons become dissociated from their gas atoms, leaving positively charged ions). Above 100,000 oK, most matter ionizes into a plasma. While the earth is a relatively plasma-free bubble (aside from fluorescent lights, lightning discharges, and magnetic fusion energy experiments) 99.9% of the universe is in the plasma state (e.g. stars and most of interstellar space). Though a plasma is a gas, the dominance of collective interactions makes the behavior quite different from that described by gas dynamics. The so-called plasma parameter g = [8/1'e 2 J3/2 /-:" (e is kT