Modelling magnetic field of a compact electro-magnetic device of experimental setup to study ROT effects in fission of heavy nuclei

Abstract The aim of the paper is to obtain a high-precision solution in a given area of the electromagnetic device of the experimental facility for studying ROT effects in heavy nuclear fission. The simulation of magnetic field is based on the well-known formulation of the magnetostatics problem for two scalar potentials. Taking into account specific configuration features of this device and the requirements to the level of homogeneity of the magnetic field, the discretization of the continuous problem using the continuous Galerkin method leads to systems whose dimensions reach 1.7 · 107. The solution of such systems is carried out with the help of a new economical variant of the matrix-free preconditioned gradient method with partitioning of the calculation domain into subdomains, which is efficient for multicore computations. As the result, the required homogeneity of the magnetic field is obtained at the level of 10 −4 in the volume of location of the 3 He spin filter.