Hypergravity effects on glide arc plasma

The behaviour of a special type of electric discharge – the gliding arc plasma – has been investigated in hypergravity (1g –18g) using the Large Diameter Centrifuge (LDC) at ESA/ESTEC. The discharge voltage and current together with the videosignal from a fast camera have been recorded during the experiment. The gliding of the arc is governed by hot gas buoyancy and by consequence, gravity. Increasing the centrifugal acceleration makes the glide arc movement substantially faster. Whereas at 1g the discharge was stationary, at 6g it glided with 7 Hz frequency and at 18g the gliding frequency was 11 Hz. We describe a simple model for the glide arc movement assuming low gas flow velocities, which is compared to our experimental results

[Exponential distance laws for satellite systems]

A revised Titius-Bode law for the solar system was proposed by Basano and Hugues (1979), by introducing three missing planets. This law can be written /b a//sub n/= alpha beta /sup n/ (with alpha =0.2853 AU and beta =1.5226), which gives the distances /b a/ /sub n/ of the /b n/th planet for successive integers /b n/. An new method is proposed to find this Basano-Hugues law for the solar system. Based upon the comparison of the ratios of successive distances, this method can be applied to the satellite systems of the three giant planets, Jupiter, Saturn and Uranus by introducing `missing satellites' to fill the gaps in satellites sequences. Three exponential distance relations are found similar to that of Basano-Hugues. All the empty places in the inner parts of satellite systems are occupied by rings and small satellites. In the Uranian system, there are two empty places which could be filled by new undiscovered small satellites.Francai

Revised exponential distance relation for the Uranian system after the Voyager 2 fly-by

The rings and satellites discovered by Voyager 2 in the Uranium system confirm the existence of small satellites and rings foreseen before their discoveries and close to the locations suggested by an exponential distance relation found by the method of comparison of the magnitude order of successive distance ratios of the large Uranium satellites. A new exponential distance relation is deduced, fitting the distances of the large satellites and groups of rings and new small satellites with a spacing ratio of 1.456. Some characteristics of a hypothetical parent body for the new inner satellites are also deduced.Anglai

Parabolic flights with the Fouga Magister aircraft

Rapport nr ESA-WPP-90info:eu-repo/semantics/publishe