Nonextensivity and the <Emphasis Type="Italic">q</Emphasis>-distribution of a relativistic gas under an external electromagnetic field

We investigate the nonextensivity and the q-distribution of a relativistic gas under an external electromagnetic field. We derive an expression for the nonextensive parameter q based on the relativistic generalized Boltzmann equation, the relativistic q-H theorem and the relativistic version of the q-power-law distribution function in the nonextensive q-kinetic theory. We thus provide the connection between the parameter q≠1 and the spatial-temporal derivatives of the temperature field of the gas as well as the four-potential, and thereby present a clearly physical meaning for the nonextensivity for the relativistic gas.