The plasma crystal

A complex plasma is a multi-component low-temperature plasma containing microparticles, for example, dust, in addition to ions, electrons, and neutral gas atoms. Under certain conditions these microparticles can form a regular structure, a plasma crystal. This new form of matter provides a unique possibility for studying phase transitions and dynamical aspects of many-body systems at the microscopic level. Complex plasmas play an important role in astrophysics as well as in technology. We describe an undergraduate experiment in which students can produce and investigate the plasma crystal and the transition to the liquid phase. (c) 2005 American Association of Physics Teachers.