[en] For the KUTI-20 induction accelerating system (LUEhK-20) the correlation functions of random processes connected with fluctuations of the main parameters of the accelerating electric field Esub(z) forming system are determined. These are the peak value of accelerating voltage on gaps, the shift of the inductor as a unite, the shift of gaps inside the inductors and the axial dimensions of the gaps. Permissible values of their spread required for the self-focusing electron-ion ring stable acceleration in electric and guiding magnetic fields are determined. It is shown that the spread of the magnetic system parameters exerts a decisive influence on the formation of dipole oscillations in the accelerating electron-ion ring. It is also shown that the tolerances on the spread of Esub(z) forming system parameters proved to be by two orders less rigid than tolerances on the magnetic system parameters and can be easily realized