The present disclosure is directed to axial strapping of a multi-core (cascaded) magnetron. The multi-core (cascaded) magnetron includes a cathode and a plurality of cores (anodes) arranged in an axial direction along the cathode. Each of the cores may have a plurality of vanes arranged periodically in an azimuthal direction along a circumference of the cathode and forming by such a way a plurality of resonant cavities. The multi-core (cascaded) magnetron further includes groups of axial straps coupling each of the cores together in the axial direction along the cathode. For example, a first group of axial straps couple the first plurality of vanes of a first core to the second plurality of vanes of a second core. In an embodiment, the axial straps are configured to provide phase synchronization of electromagnetic oscillations induced inside each of the plurality of cores.