Casimir Effect in 2D Stringy Black Hole Backgrounds

We consider the two-dimensional ``Schwarzschild'' and ``Reissner-Nordstr\"om'' stringy black holes as systems of Casimir type. We explicitly calculate the energy-momentum tensor of a massless scalar field satisfying Dirichlet boundary conditions on two one-dimensional ``walls.'' These results are obtained using the Wald's axioms. Thermodynamical quantities such as pressure, specific heat, isothermal compressibility and entropy of the two-dimensional stringy black holes are calculated. A comparison is made between the obtained results and the laws of thermodynamics. The results obtained for the extremal $(Q=M)$ stringy two-dimensional charged black hole are identical in all three different vacua used, a fact that indicates its quantum stability.