Generation of Megagauss Fields in Indestructible Solenoids with Quasi-Force Windings

The application of solenoids with force-free windings and uniformly loaded back current zones allows the avoidance of the exponential rise of radial coil size in fields higher than one megagauss that is distinctive for uniformly loaded solenoids with azimuthal current. Considered here is the possibility of a real quasi-force-free magnet system analogous to a force-free one. The coil consists of N current layers. For two types of windings the opportunity of decreasing static stresses N or N² times, respectively, is shown compared to magnetic field pressure at the coil axis is shown. An estimate of coil geometric sizes satisfying the mechanical strength and heating conditions in fields higher than one megagauss is presented. The possibility of voltage decrease between coil layers is considered, an estimate of energy is presented and the problem of the geometric shape of quasi-force-free magnets is discussed.