The Sun moves with a velocity of about 20 km s -1 relative to the local interstellar medium. The solar wind produces a bow shock ahead of the Sun. It is anticipated that the Pioneer 11 or Voyager deep space probes will eventually confirm the existence of this boundary. In contrast, ions and charged dust grains are probably deflected by the advancing heliosphere.
Cosmic rays are relativistic particles and therefore penetrate the heliosphere.
The most local gas we can associate with the local interstellar medium has the properties of the warm neutral medium. The solar radiation is backscattered by the local medium.