Probing the mechanism of interaction of Josephson vortices and pancake vortex lines in Bi$_2$Sr$_2$CaCu$_2$O$_{8+x}$ with columnar defects

Attractive interaction between pancake-vortex lines (PVLs) and Josephson vortices (JVs) in layered high-temperature superconductors is attributed to the local polarization of PVL at a crossing point by the currents circulating around the JV. To verify this mechanism we measured the Josephson flux-flow resistance in Bi-2212 stacked structures in a presence of PVLs for two cases, when PVLs are free and when they are trapped by columnar defects that highly suppress their local polarization. We found that the trapping PVLs by columnar defects (CDs) significantly eliminates interaction between PVLs and JVs. That observation strongly supports the local PVL polarization as a mechanism for their attractive interaction with JVs.