| Autor: |
Keith R Fuhrhop, Brian E. Gilchrist |
| Rok vydání: |
2005 |
| Předmět: |
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| Zdroj: |
41st AIAA/ASME/SAE/ASEE Joint Propulsion Conference & Exhibit. |
| DOI: |
10.2514/6.2005-4435 |
| Popis: |
This paper presents the theoretical analysis and modeling of an electrodynamic tether (EDT) system under an assortment of mission scenarios and physical constraints with a focus on comparing electron emission technologies used at one end of the tether. There are three different types of electron emitters considered: thermionic cathodes, field emitter arrays, and hollow cathodes. Each is evaluated for its potential use in three different system architectures: basic grounded-emitter, basic grounded-gate and series-bias system architectures. The overall results show how the efficiencies and power consumptions change depending on the mission objectives. We show what configurations yield the best performance under an array of constraints for both boosting and de-boosting tethers. Nomenclature A = constant in Richardson Eq. [A/cm 2 ] Ae = area of emitter [m 2 ] B = constant in Fowler Nordheim equation [A/V 2 ] BNorth = magnetic flux density in north direction [T] C = constant in Fowler Nordheim equation [V] D = distance across sheath [m] dl = unit distance [m] dF = force per unit distance [N] e = electric charge [C] eo = permittivity constant [F/m] η = thermionic cathode efficiency (~0.97) F = electric field in [V/m] ICL = space charge limited current [A] It = current in the tether [A] J = current density [A/m 2 ] k = Boltzmann's constant in [J/K] me = mass of electron [kg] ф = work function of element in [eV] ρ = perveance [pervs] rb = radius of emitter [m] T = temperature [K] To = energy of emitted electrons [eV] V = plasma sheath gap potential [V] Vemf = electro motive force [V] ∆Vtc = potential across the thermionic cathode [V] vorb = orbital velocity with respect to local plasma [m/s] W = width of the emitter [m] |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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