Authors: Vladimir Florinski (University of Alabama in Huntsville), Juan Alonso Guzman (University of Alabama in Huntsville), Lingling Zhao (University of Alabama in Huntsville)

The Very Local Interstellar Medium (VLISM) is the region of space that is external to the heliosphere, but is influenced by the heliospheric phenomena, including the solar-wind propagating structures and the charged particles accelerated inside, and later converted to neutral atoms. Since crossing the heliopause the Voyager space probes discovered that the VLISM was not a quiet featureless region, but a dynamic, changing environment. On long timescales Voyager 1 observed a sequence of shock and pressure waves, occurring about once every 2-3 years. These were shown to be the remnants of merged interaction regions incident on the heliopause from the solar side. On shorter timescales, the VLISM plasma was observed to be in a turbulent state, but with the magnitude of magnetic fluctuations smaller than in the heliosheath at the same wavenumber. Unlike typical solar-wind turbulence, close to the heliopause substantial power spectral energy was contained in compressible fluctuations characterized by a large longitudinal field component. As the Voyager’s distance from the heliopause increased, the fluctuations became more transverse, and by 2023 became almost incompressible. In this talk I will review these observations and discuss their possible origins, such as the interstellar medium, the solar activity within the heliosphere, and the dynamical processes on the heliopause. I will also discuss the implications of the VLISM turbulence for cosmic ray transport, including scattering and cross-field diffusion.