Warm dense matter

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.

[1] Typically, WDM has a density somewhere between 0.01 and 100 g/cm3 and a temperature on the order of several thousand kelvins (somewhere between 1 and 100 eV, in the units favored by practitioners).

WDM is expected in the interiors of giant planets, brown dwarfs, and small stars.

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