New insights in the interstellar dust properties and its interaction with the heliosphere from data, simulations and experiments

Abstract:

Interstellar dust moves through the heliosphere at velocities of ca. 26 km/s due to the relative motion of the local interstellar cloud and the solar system. On their way through the solar system, these charged particles’ trajectories are affected by solar radiation pressure force, gravity and Lorentz force, causing them to deviate in a temporal and in a spatial way that depends on the particle properties and on the interplanetary magnetic field. Combining 16 years of Ulysses interstellar dust data with Monte Carlo simulations of these particle trajectories in the inner heliosphere have unveiled new insights in the interstellar dust flow, the dust properties and it can be used to explore the nature of the outer heliosphere.

We start the talk with an overview of the current state of the art of the local interstellar dust research. We then explain the simulations and put them in the context of the Ulysses data. Using these, we demonstrate that the particles are likely to be porous, and we show why a model of dust propagation through the outer heliosphere is needed to provide a final proof. Also, we discuss the steps needed to determine from the simulations, data, and experiments how porous or fluffy the interstellar dust is. Finally, we explain how ISD data can be used as an extra ‘measureable’ to explore the structure of the outer heliosphere and we conclude the talk with a summary of how this enhances our knowledge of ISD and the LIC.