[en] Magnetic diagnostic methods are successfully used in tokamaks, but a direct application of these methods in stellarators gives little effect. However an additional measuring of magnetic fields in helical plasma current permits to obtain information about the limit parameters of magnetic configuration and additional integral relations compared with tokamaks. Measurements of plasma current magnetic fields outside the plasma confinement volume in stellarators with account of the helical structure of stellarator magnetic configuration permit to determine the profiles of important plasma parameters and magnetic configuration. 21 refs. (author)