Discussion of parameters, lattices and beam stability for a 200-TeV low-field collider

Recently, it has been suggested that improved technology and reduced costs in remotely-drilled small-diameter tunnels, coupled with improvements in robotic technology, may make the original concept of the ``desertron`` more realistic and affordable. In this concept, a long, small-diameter tunnel is drilled (<{approximately}1m diameter ``sewer`` pipe) and filled with long, low-cost magnets, which are installed and serviced robotically. To obtain high-energy then requires low cost magnets, which are iron-dominated ``superferric`` magnets (B{approximately}2 T). A large circumference is then required ({approximately}1000 km for {approximately}100 TeV/beam). Table 1 shows parameters for a 200 TeV proton-proton collider, based on the premise of a large low-cost ring with super-ferric magnets. While outline designs for a low-cost {approximately}2T dipole have been initiated, an accelerator requires beam stability, which means quadrupole fields for focusing, as well as sextupoles for chromatic correction, and further design tolerances and correctors to obtain sufficiently linear fields. Previously we have developed initial lattices and dynamic motion discussions for the earlier 40 TeV incarnation of the superferric supercollider. In this note we apply those results to initiate discussions of the dynamic requirements of this 200 TeV collider