5.7 Discussion5 Relativistic Thermodynamics of Gases. 5.5 Specific Results for a

5.6 Characteristic Speeds in a Viscous, Heat-Conducting Gas 

We recall from Section  2.4, in particular (14Popup Equation), that the jumps tex2html_wrap_inline3571 across acceleration waves and their speeds of propagation are to be calculated from the homogeneous system

  equation1771

In the present context, where the field equations are given by (79Popup Equation, 80Popup Equation) this homogeneous algebraic system spreads out into three equations, viz.

  equation1780

By (89Popup Equation) and (91Popup Equation) this is a fully explicit system, if the thermal equation of state tex2html_wrap_inline4351 is known. The vanishing of its determinant determines the characteristic speeds. Seccia & Strumia [44] have calculated these speeds - one transversal and two longitudinal ones - for non-degenerate gases and obtained the following results in the non-relativistic and ultra-relativistic cases

tabular1794

  equation1820

All speeds are finite and smaller than c . Inspection shows that in the non-relativistic limit the order of magnitude of these speeds is that of the ordinary speed of sound, while in the ultra-relativistic case the speeds come close to c .



5.7 Discussion5 Relativistic Thermodynamics of Gases. 5.5 Specific Results for a

image Speeds of Propagation in Classical and Relativistic Extended Thermodynamics
Ingo Müller
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