Bare-tether cathodic contact through thermionic emission by low-work-function materials

Xin, Chen; Sanmartin, J R

doi:10.1063/1.4736987

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Bare-tether cathodic contact through thermionic emission by low-work-function materials

Xin, Chen·Sanmartin, J R

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Abstract

A new material, C12A7:e{sup -} electride, which might present a work function as low as 0.6 eV and moderately high temperature stability, was recently proposed as coating for floating bare tethers. Arising from heating under space operation, current is emitted by thermionic emission along a thus coated cathodic segment. A preliminary study on the space-charge-limited (SCL) double layer in front of the cathodic segment is presented using Langmuir's SCL electron current between cylindrical electrodes and orbital-motion-limited ion-collection sheath. A detailed calculation of current and bias profiles along the entire tether length is carried out with ohmic effects and the transition from SCL to full Richardson-Dushman emission included. Analysis shows that in the simplest drag mode, under typical orbital and tether conditions, thermionic emission leads to a short cathodic section and may eliminate the need for an active cathodic device and its corresponding gas feed requirements and power subsystem, which results in a truly 'propellant-less' tether system for such basic applications as de-orbiting low earth orbit satellites.

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70 PLASMA PHYSICS AND FUSION TECHNOLOGY COATINGS CYLINDRICAL CONFIGURATION DRAG ELECTRODES ELECTRONS EV RANGE HEATING IONS MATERIALS ORBITS PLASMA SHEATH SATELLITES SPACE CHARGE TEMPERATURE RANGE 0400-1000 K THERMIONIC EMISSION WORK FUNCTIONS

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Xin, Chen, Sanmartin, J R. 2012-07-15. Bare-tether cathodic contact through thermionic emission by low-work-function materials. https://doi.org/10.1063/1.4736987

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