The exchange of energy between the plasma mantle and the plasma sheet boundary layer (PSBL) is examined with a one-dimensional magnetotail model. The energy exchange occurs via Poynting flux generated by the localized mode conversion of a surface wave to an Alfv¿n wave. This Poynting flux propagates through the lobe and into the PSBL where it is absorbed by two processes. The first arises from a gradient in the plasma &bgr; causing a smooth absorption of Poynting flux. The second process results from the localized mode conversion of the decaying surface wave to an Alfv¿n wave, causing a localized absorption of energy. A numerical solution of the linearized ideal MHD equations is obtained by assuming an adiabatic equation of state. The energy flux absorbed within the PSBL is of the order of 1 &mgr;W/m2 (assuming a fluid displacement of 1 RE at the plasma mantle) and varies with central plasma sheet temperature in a manner capable of triggering a thermal catastrophe in the boundary layer. ¿ American Geophysical Union 1990