Toroidal field coil and central solenoid modernization for Globus-M tokamak

The Globus-M spherical tokamak placed in A.F. Ioffe Institute is in operation since March 1999. The Globus-M tokamak peculiarity is its small aspect ratio plasma properties (R/a=1.5). Major parameters of the Globus-M tokamak are: plasma major radius 0.36 m, plasma minor radius 0.24 m, toroidal magnetic field 0.5 T, plasma current 0.3 MA and pulse length 0.3 s. Manufacturing of toroidal field coils required high accuracy of processing and high quality of contact surfaces. Winding uniformity of the conductor, both between turns, and on layers in the radial direction was required for the central solenoid. The ability to change a toroidal field coil together with providing access to the vacuum vessel manholes without disassembly of the machine is discussed. Calculations indicating dependence of magnetic flux distribution from central solenoid winding quality are presented