Plasma Wave Observations Near Jupiter: Initial Results from Voyager 2

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Science  23 Nov 1979:
Vol. 206, Issue 4421, pp. 987-991
DOI: 10.1126/science.206.4421.987


This report provides an initial survey of results from the plasma wave instrument on the Voyager 2 spacecraft, which flew by Jupiter on 9 July 1979. Measurements made during the approach to the planet show that low-frequency radio emissions from Jupiter have a strong latitudinal dependence, with a sharply defined shadow zone near the equatorial plane. At the magnetopause a new type of broadband electric field turbulence was detected, and strong electrostatic emissions near the upper hybrid resonance frequency were discovered near the low-frequency cutoff of the continuum radiation. Strong whistler-mode turbulence was again detected in the inner magnetosphere, although in this case extending out to substantially larger radial distances than for Voyager 1. In the predawn tail region, continuum radiation was observed extending down to extremely low frequencies, ∼ 30 hertz, an indication that the spacecraft was entering a region of very low density, ∼ 1.0 x 10–5 per cubic centimeter, possibly similar to the lobes of Earth's magnetotail.