The motion of a plasma flux is studied in the toroidal system with crossed radial electric and longitudinal magnetic fields. It is shown that the particle motion occurs within the dynamic boundary which is narrower than the region of electrostatic and magnetic confinement. In this case it is the electric field that plays a predominant role in the ion transport. The effect of input conditions on the flux passage through the system is analysed. It is found that the change of the radius of curvature of the magnetic field lines in the input section causes the appearance of the electric field component directed against the flux motion and essentially influences the effectiveness of particle transport. Good agreement between theory and experiment is obtained.