ON
THE THICKNESS OF A MILDLY RELATIVISTIC COLLISIONAL SHOCK WAVE
A. Kandus (IAG/USP), J.A.S. Lima (DFTE/UFRN) and R. Opher (IAG/USP)
We consider an imperfect
relativistic fluid which develops a shock wave and discuss its structure and
thickness, taking into account the effects of viscosity and heat conduction in
the form of sound absorption. The junction conditions and the non linear
equations describing the evolution of the shock are derived with the corresponding
Newtonian limit discussed in detail. As happens in the non relativistic regime,
the thickness is inversely proportional to the discontinuity in the pressure,
but new terms of purely relativistic origin are present. Particularizing for a
polytropic gas, it is found that the pure viscous relativistic shock is thicker
than its nonrelativistic counterpart, while the opposite holds for pure heat
conduction.