The Charged Particle Environment of Titan

Since magnetospheres of other planets around the solar system are composed of highly charged ions and electrons, it is only natural to be intrigued and study the effects of that magnetosphere on the planet's satellites, such as the effects on Saturn's largest moon Titan, for example.

As Cassini approached Saturn, its Ion and Neutron Camera was able to take data that lead to a determination of the Magnetosphere and Magnetopause. In the image below, excitation of hydrogen ions gives rise to the orange glow that indicates the extent of the magnetosheath.

Saturn's moon Titan is the second largest in the solar system -- and the only one with a dense atmosphere. The atmosphere, nitrogen and methane, resembles that of the early Earth. NASA's Cassini spacecraft peered through the atmosphere, imaged the haze layers -- and ESA's Huygens probe landed on the surface. Now, scientists are analyzing the ninth flyby of Titan, or T9 flyby, which took place on December 26, 2005. They have measured the ion measurements of the Cassini Plasma Spectrometer. Surprisingly, they found that the plasma flow and magnetic field directions in the distant plasma environment of Titan were distinctly different than other flybys. The ion measurements of the Cassini Plasma Spectrometer were presented, and the scientists discovered that the plasma flow and magnetic field directions in the distant plasma environment of the moon were distinctly different from the other flybys.

The T9 flyby was really outstanding because neither the flow direction, nor the magnetic field configuration was even close to their average values. Two special regions were observed along the sc orbit where the ion energy was lower than the ambient magnetospheric flow, and the electron density was higher. The scientists theorize that the second region (event-2) belongs to the distant tail region of Titan, whereas "event-1" was the result of a specific magnetic field configuration that allowed ions to escape by spiraling along the magnetic field lines towards the spacecraft from the mantle of Titan.

Click here to read the full paper, published November 6, 2007, in Geophysical Research Letters, vol. 34, l24s03, doi:10.1029/2007gl030677, 2007.

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