The radiation impedance of electrodynamic tethers in a polar Jovian orbit

Sánchez-Torres, Antonio; Sanmartin, J. R.; Donoso, José; Charro, M.

doi:10.1016/j.asr.2009.12.007

Cited by 6 publications

(21 citation statements)

References 15 publications

(18 reference statements)

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“…Tethers might be used as alternative to solve the severe power generation problem. An electrodynamic tether, which is a very long wire capable to generate the suggested power, might radiate waves to satisfy communication requirements itself (Sanchez-Torres et al, 2010). The large electromotive force produced by the tether moving in some plasma ambient near the planet generate induced current and then electric power (Sanmartin et al, 1993).…”

Section: Resultsmentioning

confidence: 99%

Radioisotope Power Systems for Space Applications

Sánchez-Torres¹

2011

Radioisotopes - Applications in Physical Sciences

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Section: Resultsmentioning

confidence: 99%

Radioisotope Power Systems for Space Applications

Sánchez-Torres¹

2011

Radioisotopes - Applications in Physical Sciences

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“…The Alfvén impedance Z A was determined for the first orbit and both equatorial and polar region cases. High Alfvén velocity V A found in paper 2 gives high Alfvén impedance too, because of Z A ∝ V A . Additionally, there are two contributions to the Alfvén impedance, involving logarithmic terms that depend of both tether length and contactor size.…”

Section: Introductionmentioning

confidence: 96%

“…In the present work we generalize the paper 2 work, considering the radiation impedance for both Alfvén and FM waves, and both Juno and LJO missions. Anticipating that the wave vector k will be nearly perpendicular to the ambient magnetic field in all cases considered, k ≃ k , the Doppler relation reads

greatly simplifying the calculation of impedances.…”

Section: Introductionmentioning

confidence: 99%

“…This work was followed by later authors [ Barnett and Olbert , 1986; Dobrowolny and Veltri , 1986; Hastings and Wang , 1987, 1989; Estes , 1988; Donohue et al , 1991; Sanmartin and Martinez‐Sanchez , 1995] (hereinafter referred to as paper 1) considering the cold plasma approximation. Recently, Biancalani and Pegoraro [2010b] considered radiation by a loop current inside a satellite orbiting in LEO, and Sanchez‐Torres et al [2010] (hereinafter referred to as paper 2) carried out a preliminary study of the Alfvén impedance of a tether in a Juno‐like orbit at the Jovian magnetosphere. The Alfvén impedance Z A was determined for the first orbit and both equatorial and polar region cases.…”

Section: Introductionmentioning

confidence: 99%

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Tether radiation in Juno-type and circular-equatorial Jovian orbits

Sánchez-Torres

Sanmartin

2011

J. Geophys. Res.

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Wave radiation by a conductor carrying a steady current in both a polar, highly eccentric, low perijove orbit, as in NASA's planned Juno mission, and an equatorial low Jovian orbit (LJO) mission below the intense radiation belts, is considered. Both missions will need electric power generation for scientific instruments and communication systems. Tethers generate power more efficiently than solar panels or radioisotope power systems (RPS). The radiation impedance is required to determine the current in the overall tether circuit. In a cold plasma model, radiation occurs mainly in the Alfvén and fast magnetosonic modes, exhibiting a large refraction index. The radiation impedance of insulated tethers is determined for both modes and either mission. Unlike the Earth ionospheric case, the low‐density, highly magnetized Jovian plasma makes the electron gyrofrequency much larger than the plasma frequency; this substantially modifies the power spectrum for either mode by increasing the Alfvén velocity. Finally, an estimation of the radiation impedance of bare tethers is considered. In LJO, a spacecraft orbiting in a slow downward spiral under the radiation belts would allow determining magnetic field structure and atmospheric composition for understanding the formation, evolution, and structure of Jupiter. Additionally, if the cathodic contactor is switched off, a tether floats electrically, allowing e‐beam emission that generate auroras. On/off switching produces bias/current pulses and signal emission, which might be used for Jovian plasma diagnostics.

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“…Also, maximum N 0 is typically 10 2 times smaller than at the F-layer daytime maximum, and the Alfven velocity, V A oc BQNNQ, may be up to 10 3 times greater than in LEO. This makes impedances for Fast Magneotosonic and Alfven radiations greater for Jupiter by 2 and up to 3 orders of magnitude in (14a, b), both affecting the tether-current circuit and making significant signals possible [24]. Insertion in orbit and touring the Jovian moons afterwards, which are transport applications of interest, prove possible, a tens-of-km long tape with mass a sensible fraction of the full spacecraft mass being required.…”

Section: Bare Tethers At Jupitermentioning

confidence: 99%

A review of electrodynamic tethers for science applications

Sanmartin

2010

Plasma Sources Sci. Technol.

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Abstract. A bare electrodynamic tether (EDT) is a conductive thin wire or tape tens of kilometres long, which is kept taut in space by gravity gradient or spinning, and is left bare of insulation to collect (and carry) current as a cylindrical Langmuir probe in an ambient magnetized plasma. An EDT is a probe in mesothermal flow at highly positive (or negative) bias, with a large or extremely large 2D sheath, which may show effects from the magnetic self-field of its current and have electrons adiabatically trapped in its ram front. Beyond technical applications ranging from propellantless propulsion to power generation in orbit, EDTs allow broad scientific uses such as generating electron beams and artificial auroras; exciting Alfven waves and whistlers; modifying the radiation belts; and exploring interplanetary space and the Jovian magnetosphere. Asymptotic analysis, numerical simulations, laboratory tests, and planned missions on EDTs are reviewed.

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The radiation impedance of electrodynamic tethers in a polar Jovian orbit

Cited by 6 publications

References 15 publications

Radioisotope Power Systems for Space Applications

Radioisotope Power Systems for Space Applications

Tether radiation in Juno-type and circular-equatorial Jovian orbits

A review of electrodynamic tethers for science applications

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