were there any exploration done to study on this?
Until 2009 eight spacecraft have flown around Jupiter including Pioneer 10, Pioneer 11, Voyager 1 and  Voyager 2
Magnetosphere of Jupiter
As of 2009 a total of eight spacecraft have flown around Jupiter and all have contributed to the present knowledge of the Jovian magnetosphere. The first space probe to reach Jupiter was Pioneer 10 in December 1973, which passed within 2.9 "R" from the center of the planet. Its twin Pioneer 11 visited Jupiter a year later, traveling along a highly inclined trajectory and approaching the planet as close as 1.6 "R".
what is magnetosphere of jupiter? The cavity created in the solar wind by the planet's magnetic field how big is the cavity? It extends up to seven million kilometers in the Sun's direction and almost to the orbit of Saturn in the opposite direction which scientist discovered it? UNANSWERABLE
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Magnetosphere of Jupiter [SEP] Exploration after 1970
Voyagers 1 and 2 arrived at Jupiter in 1979–1980 and traveled almost in its equatorial plane. Voyager 1, which passed within 5 "R" from the planet's center, was first to encounter the Io plasma torus. It received a radiation dosage one thousand times the lethal level for humans, the damage resulting in serious degradation of some high-resolution images of Io and Ganymede. Voyager 2 passed within 10 "R" and discovered the current sheet in the equatorial plane. The next probe to approach Jupiter was Ulysses in 1992, which investigated the planet's polar magnetosphere.