Multiscale Structure of the Heliospheric Magnetic Field Strength and Solar Wind Speed: Multifractal Structure and Distribution Functions

The Sun is surrounded by a region called the `heliosphere', which has been explored by the Voyager 1 spacecraft to 85 AU and beyond. The heliosphere is filled with magnetic fields and plasmas moving from the Sun toward the interstellar medium at supersonic speeds. The magnetic fields and have plasmas a variety of sources on the Sun and they move with a broad range of speeds, so that they interact as they move away from the Sun. The diversity of the flows and their interactions on a wide range of scales lead to a complex, evolving heliospheric structure. On scales from 1 to 26 days the magnetic field and speed variations can be described by multifractals, power spectra, and probability distribution functions on various scales. The radial evolution of the multi-scale structure of the large-scale fluctuations in the heliosphere can be described and predicted by a deterministic multi-fluid MHD model, with observations at 1 AU as input conditions.