Biography:

In the past Alain Lecacheux has collaborated on articles with Nicole Meyer-Vernet. One of their most recent publications is Solar system, low frequency radio astronomy from the moon. Which was published in journal Advances in Space Research.

More information about Alain Lecacheux research including statistics on their citations can be found on their Copernicus Academic profile page.

Alain Lecacheux's Articles: (2)

Solar system, low frequency radio astronomy from the moon

AbstractRadio astronomy, particularly radio astronomy at low frequencies (< 100 MHz) is becoming more and more difficult to operate from Earth-based observatories because of the proliferation of manmade interferences. At frequencies lower than 10 MHz, observations are rarely possible,or impossible, because of the opacity of the terrestial ionosphere. An observatory on the Moon is an ideal place for low frequency, solar system radio astronomy. The highly magnetized planets have been shown to produce powerful low frequency radio emissions. A broadband and sensitive radiotelescope, having an high spectral resolution capability, would allow correlative studies of these radiations and their relation with the solar activity. Monitoring of the solar radio emissions and in situ measurements when the Moon moves in the Solar wind or inside the terrestial magnetosphere, will also be subjects of great interest.

Regular ArticleConstraints on Saturn's E Ring from the Voyager 1 Radio Astronomy Instrument

AbstractWe have reanalyzed the data acquired by the planetary radioastronomy (PRA) experiment during the passage of Voyager 1 through Saturn's E ring. Depending on the distance from the ring plane, the instrument detected (i) dust grain impacts on the spacecraft and/or (ii) plasma waves or noise. The signal produced by the dust can be recognized by its power spectrum. It is dominant in a region of ≈12,000 km vertical extent around the ring plane, and has a maximum at roughly 5000 km southward of equator (at 6.1RSfrom Saturn). Assuming that the grain concentration is given by the model of Showalteret al.(Showalter, M. R., J. N. Cuzzi, and S. M. Larson 1991.Icarus94, 451–473) derived from optical observations, we infer from the mean PRA voltage and from the histogram of the data that the particles have a mean radiusr≈ 1 μm and a narrow size distribution of fractional dispersion between 10 and 30%. These values agree with the above model. We have also investigated the ring thickness. The PRA signal has a full vertical width at half-maximum of ≈8000 km, which is 2.3 times less than that given by the optical model. Since the signal produced by the dust varies strongly with the grain size (asr6), our measurements can be made compatible with the optical observations if the particle mean size decreases slightly with vertical distance, by about 10% over 4000 km.

Advertisement
Join Copernicus Academic and get access to over 12 million papers authored by 7+ million academics.
Join for free!

Contact us