Jupiter’s enormous magnetic field is nearly 20,000 times as powerful as Earth’s field. The field dominates a vast area of space called the magnetosphere, where it traps swarms of charged particles — electrons and ions. Some of these particles become trapped in an intense radiation belt near the planet, creating a hazard for visiting spacecraft. The Jovian magnetosphere has a tadpole shape, ballooning outward 600,000 to 2 million miles (1 to 3 million kilometers) toward the sun and tapering into a long tail that extends more than 600 million miles (1 billion kilometers) outward from Jupiter, to as far as Saturn’s orbit.
Listen to the “Roar” of Jupiter, as described by NASA’s JPL, as Juno approaches the planet.
The spacecraft crossed into Jupiter’s magnetic field on June 24th, 2016 and recorded the crossing on its Wave instrument (not an actual soundwave).
This is called the Bow Shock; where the solar wind is heated and slowed by the Jupiter’s magnetosphere (Magnetic Field).
The next day, Juno’s Wave instrument captured the moment it crossed the magnetopause; the boundary between the Sun’s magnetic field and Jupiter’s magnetosphere.
From Why With Nye Jupiter series, here is what Juno has to deal with the “Roar”
Juno is in its Jupiter Orbit Insertion phase. It is scheduled to establish a 53.5 Earth-day orbit on July 4th (PDT). As part of the command sequence for Juno, a burn will start at 2035 PDT to slow it down for orbit insertion.