NASA’s venerable spacecraft, Voyager 1, has entered the farthest reaches of our solar system ahead of hitting interstellar space. Scientists refer to this new region as a magnetic highway for charged particles because our Sun’s magnetic field lines are connected to interstellar magnetic field lines. This connection allows lower-energy charged particles that originate from within the heliosphere to zoom out and lets higher-energy particles from outside stream in.
NASA Voyager 1 Encounters New Region in Deep Space – NASA Jet Propulsion Laboratory.