Plasma Physics

In physics and chemistry, a plasma is an ionized gas, and is usually considered to be a distinct phase of matter. "Ionized" in this case means that at least one electron has been dissociated from a significant fraction of the [atoms or] molecules. The free electric charges make the plasma electrically conductive so that it couples strongly to electromagnetic fields. This fourth state of matter was first identified by Sir William Crookes in 1879 and dubbed "plasma" by Irving Langmuir in 1928, because it reminded him of a blood plasma.

Plasmas are the most common phase of matter. The entire visible universe outside the solar system is plasma: all we can see are stars. Since the space between the stars is filled with a plasma, although a very sparse one (see interstellar- and intergalactic medium), essentially the entire volume of the universe is plasma (see astrophysical plasmas). In the solar system, the planet Jupiter accounts for most of the non-plasma, only about 0.1% of the mass and 10⁻¹⁵ of the volume within the orbit of Pluto. Alfvén also noted that due to their electric charge, very small grains also behave as ions and form part of a plasma (see dusty plasmas).

The NRL Plasma Formulary has been the mini-Bible of plasma physicists for the past 25 years. It is an eclectic compilation of mathematical and scientific formulas, and contains physical parameters pertinent to a variety of plasma regimes, ranging from laboratory devices to astrophysical objects.