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Introduction
Plasmas are any statistical systems containing mobile charged particles. When such a system is condensed, interaction between particles becomes so effective that the system may undergo changes in the internal states or the phase transitions. One applies the basic principles of statistical mechanics to elucidate the thermodynamic properties and the rates of elementary processes in such a system. We begin this volume by surveying salient examples of dense plasmas in the astrophysical and laboratory settings.
1.1 Dense Plasmas in Nature
Astrophysical dense plasmas are those we find in the interiors, surfaces, and outer envelopes of stellar objects such as neutron stars, white dwarfs, the Sun, brown dwarfs, and giant planets (e.g., Van Horn, 1991; Ichimaru, 2004b). Condensed plasmas in the laboratory setting include: metals and alloys (solid, amorphous, liquid, and compressed), semiconductors (electrons, holes, and their droplets), various realizations of dense plasmas (shock-compressed, diamond-anvil cell, metal vaporization, pinch compression), and cryogenic, nonneutral plasmas (Davidson, 1990) including pure electron- or ion-plasmas (Driscoll & Malmberg, 1983; Bollinger et al., 1990) in the electromagnetic traps or on the surfaces of dielectrics such as liquid helium (Grimes, 1978).
The physics issues in such dense plasmas are (Ichimaru, Iyetomi, & Tanaka, 1987): phase transitions, construction of the phase diagrams, and accounting for the stellar as well as magnetic structures. Phase transitions to be considered are: gas to liquid, liquid to solid (Wigner, 1935, 1938), insulator to metal (Wigner & Huntington, 1935), hadrons to quark–gluon plasmas (Yagi, Hatsuda, & Miake, 2005), and para- to ferromagnetism (e.g., Landau & Lifshitz, 1960a).
Elementary processes involved in those plasmas then include (Ichimaru & Ogata, 1995): scattering of electromagnetic waves (Rosenbluth & Rostoker, 1962; Ichimaru, 1973), photon transfers and opacities, emission of latent heat through phase transitions, electric and thermal transports, shear moduli of the crystalline solids, and enhanced thermonuclear as well as pycnonuclear reactions (Gamow & Teller, 1938; Cameron, 1959). The rates of these processes may depend sensitively on the changes in microscopic, macroscopic, thermodynamic, dielectric, and/or magnetic states of the matter. These changes of states may be associated with freezing transitions, chemical separations between the compositions, ionization or insulator-to-metal transitions, magnetic transitions, and transitions between normal to superconductive phases.
1.1.1 Astrophysical Dense Plasmas
Interiors of the main sequence stars such as the Sun are dense plasmas constituted mostly of hydrogen. The Sun has a radius, R S ≅ 6.69 × 105 km, and a mass, M S ≅ 1.99 × 1030 kg; the mass density is 1.41 g/cm3 on average. The central part of the Sun has a mass density of approximately 1.56 × 102 g/cm3, a temperature of approximately 1.5 × 107 K, and a pressure of approximately 3.4 × 105 Mbar (Bahcall & Pinsonneault, 1995). The mass fraction of hydrogen takes on a value of 0.36 near the center and 0.73 near the surface. The rate...