A numerical comparison of various techniques of non-steady magnetic stirring, such as travelling (TMF), rotating (RMF), alternating (AMF) and carousel magnetic fields (CMF), during unidirectional solidification of large rectangular silicon melts of 700 kg was performed. The comparison was focused on the time required to homogenize the distribution of a point wise released tracer in the melt. All studied magnetic fields showed identical magnetic screen and interaction parameter R-omega=80.3 and N-mag =7.9 x 10(-6), respectively. The Lorentz forces were generated in KRISTMAG (R) heater magnet modules (HMM) positioned at the side or bottom of the silicon melt container. Stirring progress was studied by tracking the formation of the concentration field of the passive tracer in already fully developed melt flow. Results revealed the superiority of the CMF concept independent of the point of injection. (C) 2012 Elsevier B.V. All rights reserved.