It is known that fast solar wind magnetic clouds cause the most significant geomagnetic disturbances. The paper presents an original method for establishing the orientation of shock wave plane of a magnetic cloud with respect to the vector of the interplanetary magnetic field. It was found that the level value of auroral substorm activity depends on this orientation. The conditions for the existence of turbulent motions in cloud sheath are formulated. It is shown that the orientation of shock wave front of the cloud determines the intensity of sheath turbulent motions, which controls the level of substorm activity.

solar plasma flow, magnetohydrodynamic disturbances, substorm activity, shock wave, interplanetary magnetic clouds.