Quantities of Spectroscopy

Abstract

The total energy emitted by a plasma as electromagnetic radiation per unit time is called itsradiative loss and plays a crucial role in all power balance considerations. As a physical quantity it is aradiant flux Ф (through the surface of the plasma), and its unit is watt (W). It is also calledradiant power.Radiant flux density φ refers to the flux per unit area φ = dΦ/dA with the unit Wm⁻², irrespective of whether the radiation is emitted from an area, crosses an imaginary surface in space, or falls onto an areaA. In this latter case, it is customary to call this flux density at the surfaceirradiance E. The energy deposited per unit area during a given time is thefluence H = ∫Edt, with the unit Jm⁻².