Ionospheric temperature and density measurements by means of spherical double probes

Fahleson, U.; Fälthammar, Carl‐Gunne; Pedersen, Å.

doi:10.1016/0032-0633(74)90122-6

Cited by 56 publications

(43 citation statements)

References 8 publications

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“…The bias voltage of the probe is varied every 24 s between −4 V and +4 V during a Titan flyby occurring at a closest approach below 1200 km. The analysis of the currentvoltage curve of the sweeps, using the Orbital Motion Limited (OML) theory (Mott-Smith and Langmuir, 1926), allows to estimate several electron and ion parameters (Fahleson et al, 1974).…”

Section: The Rpws Langmuir Probe Datamentioning

confidence: 99%

Titan's ionosphere in the magnetosheath: Cassini RPWS results during the T32 flyby

et al. 2009

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Abstract. The Cassini mission has provided much information about the Titan environment, with numerous low altitude encounters with the moon being always inside the magnetosphere. The only encounter taking place outside the magnetopause, in the magnetosheath, occurred the 13 June 2007 (T32 flyby). This paper is dedicated to the analysis of the Radio and Plasma Wave investigation data during this specific encounter, in particular with the Langmuir probe, providing a detailed picture of the cold plasma environment and of Titan's ionosphere with these unique plasma conditions. The various pressure terms were also calculated during the flyby. The comparison with the T30 flyby, whose geometry was very similar to the T32 encounter but where Titan was immersed in the kronian magnetosphere, reveals that the evolution of the incident plasma has a significant influence on the structure of the ionosphere, with in particular a change of the exo-ionospheric shape. The electrical conductivities are given along the trajectory of the spacecraft and the discovery of a polar plasma cavity is reported.

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Section: The Rpws Langmuir Probe Datamentioning

confidence: 99%

Titan's ionosphere in the magnetosheath: Cassini RPWS results during the T32 flyby

et al. 2009

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“…From the parameter results of a two-electron and one drifting ion component Orbit Motion Limited (OML) theory (Mott-Smith and Langmuir, 1926) fit to the LP Voltage sweeps (±4 V during T5) it is possible to estimate a number of cold plasma parameters. Among them are the electron number density and temperature (T e ) as well as the spacecraft potential (U SC ), but in most circumstances it is also possible to obtain values for the average ion mass (m i ), ion ram velocity (v i ), ion density (n i ), ion temperature (T i ), and solar UV intensity (e.g., Fahleson et al, 1974). LP sweeps were sampled each 24 s during the T5 flyby.…”

Section: Measurement Principlesmentioning

confidence: 99%

On magnetospheric electron impact ionisation and dynamics in Titan's ram-side and polar ionosphere – a Cassini case study

et al. 2007

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Abstract. We present data from the sixth Cassini flyby of Titan (T5), showing that the magnetosphere of Saturn strongly interacts with the moon's ionosphere and exo-ionosphere. A simple electron ionisation model provides a reasonable agreement with the altitude structure of the ionosphere. Furthermore, we suggest that the dense and cold exo-ionosphere (from the exobase at 1430 km and outward to several Titan radii from the surface) can be explained by magnetospheric forcing and other transport processes whereas exospheric ionisation by impacting low energy electrons seems to play a minor role.

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“…[8] The LP sweep data can also, in some circumstances, be used to obtain values for the average ion mass, ion ram velocity, ion density, ion temperature, and solar UV intensity [e.g., Fahleson et al, 1974]. The current to the probe for negative U bias is given by I = I i0 (1 À U bias /T i,eff ) + I ph , where the effective ion energy (T i,eff ) is the sum of the thermal random ion temperature (T i ) and the ram ion directed flow energy (m i v i 2 /2e [eV]).…”

Section: Observations Of Ionsmentioning

confidence: 99%

The inner magnetosphere of Saturn: Cassini RPWS cold plasma results from the first encounter

Wahlund

2005

Geophysical Research Letters

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We present new results from the inner magnetosphere of Saturn obtained by the Radio and Plasma Wave Science (RPWS) investigation onboard Cassini around the period of the Saturn orbit injection (July 1, 2004). Plasma wave electric field emissions, voltage sweeps by the Langmuir probe (LP) and radio sounder data were used to infer the cold plasma (<100 eV) characteristics within 20 RS of Saturn. A dense (<150 cm−3) and cold (<7 eV) plasma torus was found just outside the visible F‐ring. This torus of partly dusty plasma does not perfectly co‐rotate with Saturn, which suggests the cold plasma is electro‐dynamically coupled to the charged ring‐dust particles. The spacecraft potential was a few volts negative above the E‐ and G‐rings, indicating the dust‐particles were likewise negatively charged. The cold ion characteristics changed near the magnetically conjugate position of Dione, indicating release of volatile material from this icy moon.

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Ionospheric temperature and density measurements by means of spherical double probes

Cited by 56 publications

References 8 publications

Titan's ionosphere in the magnetosheath: Cassini RPWS results during the T32 flyby

Titan's ionosphere in the magnetosheath: Cassini RPWS results during the T32 flyby

On magnetospheric electron impact ionisation and dynamics in Titan's ram-side and polar ionosphere – a Cassini case study

The inner magnetosphere of Saturn: Cassini RPWS cold plasma results from the first encounter

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