A plasma stream was directed from a field‐free region along the axis of symmetry into a magnetic field of biconical cusped geometry. No evidence was found to support the hypothesis that a directed plasma stream can not penetrate a magnetic field whose value exceedsBc2= 12&pgr;&rgr;v2, where &rgr; is the plasma density andvits directed velocity. As the plasma penetrated the magnetic field, the plasma and field were found to intermix. Large quantities of the plasma which entered the containment region through one point cusp were found to leave promptly through the second point cusp and through the line cusp. Bombardment of the vacuum chamber walls in the vicinity of the line cusp generated sufficient secondary ions to mask any small scale plasma trapping. However, there was no evidence of gross trapping of the injected plasma.