Dynamics of the size of the 11-year modulation region of galactic cosmic rays

Time dependences of cosmic ray (CR) intensity in the stratosphere and the external heliosphere are analysed as well as their relations with time dependences of solar activity parameters. The fact of CR modulation amplification at large distances from the Sun due to shock waves is established. Thus, it is worth speaking about three physical boundaries inside the heliosphere: near, middle and far. In the region, limited by the near boundary (2-3 ua), modulation properties of the medium are mainly formed by flare shock waves and high-velocity plasma fluxes. It is possible to judge about the region size by the Forbush decrease time. In the middle region of the heliosphere modulation properties of medium are mainly formed at interaction of fast plasma fluxes with a large scale magnetic field of the solar wind; 11-year cycle of CR on the Earth orbit is mainly determined by these properties. The boundary of this region in the most part of the 11-year cycle is at the distance of approximately 15 ua. In the far region of the heliosphere modulation properties are mainly formed by shock waves strengthened in the external heliosphere