We study magnetohydrodynamic wave mode conversion as a mechanism contributing to the observed low-frequency electromagnetic fluctuation level in the plasma sheet. Low-frequency waves originating in the magnetosheath can transport energy across the tail flank magnetopause and through the tail lobes toward the plasma sheet. In the plasma sheet boundary layer and in the central plasma sheet, local conditions permit mode conversion to occur in resonant sheets. Resonant coupling to both Alfvén and slow-mode waves is possible. Energy is fed to the plasma in these resonant sheets, which may help to explain the acceleration and heating of particles observed in the plasma sheet boundary layer and the central plasma sheet.