ИСТИНА

Interstellar dust (ISD) particles penetrate the heliosphere because of the relative motion of the local interstellar cloud and the Sun. The penetrated particles pass through the heliospheric in- terface region - the region of solar wind and interstellar plasma interaction. The electromagnetic force, which is dominant in the heliospheric interface, affects the motion of positively charged ISD particles, and therefore, the ISD flow modifies after the passage through this region. In this study, we show how the heliospheric interface influences the distribution of ISD particles in the inner heliosphere. For this purpose, we develop the first model of ISD distribution in the heliosphere, which takes account of both the effects of the heliospheric interface and the rotating heliospheric current sheet. We consider the effects concerning the number density distribution and the theoretical counts on the Ulysses dust sensor. Using the model, we demonstrate that the heliospheric interface strongly influences the distribution of small ISD particles (radius a = 250 nm and smaller, for astronomical silicates) near the Sun. For the smallest considered particles (a = 150 nm), there are qualitative differences between the results obtained by the models with and without the effects of the heliospheric interface, respectively. The results of computations show that the heliospheric interface facilitates the penetration of a = 150 nm dust particles in the inner heliosphere. It contradicts the intuitive concepts that the heliospheric boundaries filter out small ISD particles. We also find out that the main effect of the heliospheric interface is the deflection of ISD particles in the outer heliosheath. We show that this deflection explicitly depends on the parameters of the interstellar magnetic field. The computations with different heliospheric models show that the ISD theoretical distribution near the Sun is sensitive to the heliospheric model used and particularly the plasma parameters in the pristine LISM. Thus, the analysis of ISD data provides a new approach for distant diagnostics of interstellar plasma parameters.