Radiative steering of warp shells

Abstract

We construct exact timelike junctions between compact flat cavities and a Kinnersley photon-rocket exterior. The shells satisfy the strict surface dominant energy condition and steer subluminally under nonnegative radiation. Burns joined at static spheres give $m_f/m_i=e^{-3L}$ for exterior velocity-space path length $L$; the supported cavity center obeys a separate sharp bound. Self-similar shells require anisotropic stress and have growing normal modes with the ambient geometry and coefficients held fixed. A separate elastic model admits local self-gravitating recoil control with outward emission. At zero gravitational coupling, exact unstrained turns yield sharp fuel bounds and travel limits at fixed duration. Limits on angular concentration and inward emission reduce efficiency. For smooth emission and positive inner-face density, stress-free recoil requires photons to enter the cavity. Self-gravitating settling after a turn remains open.

arXiv comment39 pages, 1 figure. Substantially revised and retitled. Develops the photon-recoil construction into exact steering by successive burns, with sharp mass and fuel bounds. Scope narrowed, with revised material and stability analyses; self-gravitating settling after a turn remains open