Tapering schemes for FCCee

The electron-positron Future Circular Collider (FCC-ee) is designed to operate at four beam energies, from 45.6 GeV to 182.5 GeV. At such energy levels, the circulating beam loses a significant fraction of its energy via synchrotron radiation. As a single RF insertion is foreseen in the ring, large closed-orbit shifts featuring a typical sawtooth pattern and optics distortions are induced. This in turn leads to a significant reduction of the dynamic aperture if no mitigation is implemented. The solution is to adapt the fields of the magnets to the local beam energy which is referred to as "tapering". For practical reasons, this field adjustment must be realized for groups of magnets to limit the number of powering circuits. An algorithm has bean established to self-consistently compute the tapering strengths of a given scheme, the RF phase required to compensate the energy loss and the required orbit corrections. Tapering scenarios, from coarse schemes to fine grained options are studied with the XSuite tracking code in terms of closed-orbit excursion and optics distortion. The results at the Z-pole (45.6 GeV) and $t\bar t$ (182.5 GeV) energies are discussed in detail.