Thermodynamics of the interconversion of heat and work via plasma electric fields

Abstract

Thermodynamics of a system where a group of cold charged particles locally confined in a volume V_P within a warm plasma of temperature T and volume V (V_P<V) is presented. Various thermodynamic functions of the model, e.g., Helmholtz free energy, internal energy, entropy, electrostatic pressure of charged particles, are calculated from first principles. In the homogeneous limit, an equation of state for the electrostatic (ES) pressure of charged particles is derived and the internal energy is shown to consist solely of the thermal energy of the background plasma. The interconversion of plasma heat and mechanical work via isothermal compression/expansion of plasma electric field (associated with charged particles) in a plasma heat pump and ES heat engine cycle is demonstrated. The efficiency of the plasma heat pump is discussed in terms of its power efficiency η_P and is shown to be close to unity.