Abstract This work analyzes the Darmois junction conditions matching an interior Alcubierre warp drive spacetime to an exterior Minkowski geometry. The joining hypersurface requires that the shift vector of the warp drive spacetime satisfy the solution of a particular inviscid Burgers equation, namely, the gauge where the shift vector is not a function of the y and z spacetime coordinates. Such a gauge connects the warp drive metric to shock waves via a Burgers-type equation, which was previously found to be an Einstein equation vacuum solution for the warp drive geometry. It is also shown that not all Ricci and Riemann tensor components are zero at the joining hypersurface; for that to happen, they depend on the shift vector solution of the inviscid Burgers equation at the joining wall. This means that the warp drive geometry is not globally flat.
Santos-Pereira et al. (2026) studied this question.