Warm dense matter, abbreviated WDM, can refer to either equilibrium or non-equilibrium states of matter in a (loosely defined) regime of temperature and density between condensed matter and hot

plasma Plasma or plasm may refer to: Science * Plasma (physics), one of the four fundamental states of matter * Plasma (mineral), a green translucent silica mineral * Quark–gluon plasma, a state of matter in quantum chromodynamics Biology * Blood pla ...

. It can be defined as the state that is too dense to be described by weakly coupled plasma physics yet too hot to be described by

condensed matter physics Condensed matter physics is the field of physics that deals with the macroscopic and microscopic physical properties of matter, especially the solid and liquid phases which arise from electromagnetic forces between atoms. More generally, the sub ...

. In this state, the

potential energy In physics, potential energy is the energy held by an object because of its position relative to other objects, stresses within itself, its electric charge, or other factors. Common types of potential energy include the gravitational potentia ...

of the

Coulomb interaction Coulomb's inverse-square law, or simply Coulomb's law, is an experimental law of physics that quantifies the amount of force between two stationary, electrically charged particles. The electric force between charged bodies at rest is conventiona ...

between

electrons The electron ( or ) is a subatomic particle with a negative one elementary electric charge. Electrons belong to the first generation of the lepton particle family, and are generally thought to be elementary particles because they have no ...

and ions is on the same order of magnitude (or even significantly exceeds) their thermal energy, while the latter is comparable to the Fermi energy. Typically, WDM has a density somewhere between and a temperature on the order of several thousand

kelvin The kelvin, symbol K, is the primary unit of temperature in the International System of Units (SI), used alongside its prefixed forms and the degree Celsius. It is named after the Belfast-born and University of Glasgow-based engineer and phys ...

s (somewhere between , in the units favored by practitioners). WDM is expected in the interiors of giant planets,

brown dwarf Brown dwarfs (also called failed stars) are substellar objects that are not massive enough to sustain nuclear fusion of ordinary hydrogen ( 1H) into helium in their cores, unlike a main-sequence star. Instead, they have a mass between the most ...

s, and small stars. WDM is routinely formed in the course of intense-laser–target interactions (including the inertial confinement fusion research), particle-beam–target interactions,Accelerator Driven Warm Dense Matter Workshop
/ref> and in other setups where a condensed matter is quickly heated to become a strongly interacting plasma. As such, the WDM physics is also relevant to ablation of metals (atmospheric entry from space, laser-machining of materials, etc). A WDM created using ultra-fast laser pulses may for a short time exist in a two-temperature

non-equilibrium Non-equilibrium thermodynamics is a branch of thermodynamics that deals with physical systems that are not in thermodynamic equilibrium but can be described in terms of macroscopic quantities (non-equilibrium state variables) that represent an ext ...

form where a small fraction of electrons are very hot, with the temperature well above that of the bulk matter.

References

{{DEFAULTSORT:Warm Dense Matter Plasma physics

See also

References