Micron‐sized particles detected in the vicinity of Jupiter by the Voyager plasma wave instruments

Abstract

Wideband waveform data obtained by the plasma wave instruments onboard the Voyager 1 and 2 spacecraft have been used to study micron‐sized dust particles in the vicinity of Jupiter. The technique used was developed during the fly by s of Saturn, Uranus, and Neptune, and makes use of the fact that a particle striking the spacecraft at 10–20 km/s causes a voltage pulse in the plasma wave receiver. The waveform of the voltage pulse is much different than the waveform of plasma waves and provides a highly reliable method of detecting micron‐sized dust particles. Although the dust impact rate observed in the vicinity of Jupiter is much lower than the rates at Saturn, Uranus, and Neptune, the particles are easily detectable. Approximately 1200 48‐second frames of wideband waveform data were examined in the vicinity of Jupiter. Dust impact signatures were found in approximately 20% of these frames. The peak impact rates are about 1 impact per second, and the peak number densities are about 10−5 m−3. Most of the impacts occurred near the equatorial plane at radial distances less than about 35 RJ from Jupiter. Analysis of the detection threshold indicates that the particles have masses greater than 10−11 g, which corresponds to particles with diameters of a few micrometers or larger.

Micron‐sized dust particles detected in the outer solar system by the Voyager 1 and 2 plasma wave instruments

“…Measurements obtained within about 500 planetary radii from Saturn, Uranus, and Neptune were excluded in order to avoid contamination by dust orbiting these planets. For previous analyses of dust impact measurements near these planets, see Gurnett et al [1983;1987; and Tsintikidis et al [1994Tsintikidis et al [ , 1995Tsintikidis et al [ , 1996. During the course of this study, a total of 832 frames were examined from Voyager 1, and 1308 frames were examined from Voyager 2.…”

Roles of positively charged dust in the formation of ion‐acoustic subsonic solitary waves in electron‐ion‐positively charged dust plasmas

“…There are many space plasma environments, viz. Earth's mesosphere, [18][19][20] cometary tails, [21] Jupiter's surroundings, [22] Jupiter's magnetosphere, [23] etc. where in addition to electron-ion plasmas, the pcd species have been detected.…”

“…where in addition to electron-ion plasmas, the pcd species have been detected. [18][19][20][21][22][23] There are three principal mechanisms by which the dust species becomes positively charged. [24][25][26][27] These are (a) photo-emission of electrons from the dust surface induced by the flux of photons, [26] (b) thermionic emission of electrons from the dust grain surface by the radiative heating, [25] and (c) secondary emission of electrons from the dust surface by the impact of high energetic plasma particles.…”

“…We finally hope that the results of this work should be useful for understanding the physics of nonlinear phenomena like subsonic solitary like structures in many space plasma environments, viz. Earth's mesosphere, [18][19][20] cometary tails, [21] Jupiter's surroundings, [22] Jupiter's magnetosphere, [23] etc.…”

Small-Scale Dust Structures in Halley's Coma: Evidence from the Vega-2 Electric Field Records

“…Dust impact effects recorded by the Voyager plasma wave/radio experiment at the outer planets are investigated extensively, as they still represent unique in situ observations of the dust rings; for recent results see Meyer-Vernet et al (1998) and Tsintikidis et al (1996). However, both plasma wave and dust measurements have so far been carried out in a highly dusty medium only onboard the Vega mission to Comet Halley.…”