Three dimensional fluid-kinetic model of a magnetically guided plasma jet

Ramos, J. J.; Merino, Mario; Ahedo, Eduardo

doi:10.1063/1.5026972

Cited by 17 publications

(19 citation statements)

References 38 publications

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“…The error in using this approximate law, in the wide parameter range considered, is found to be below 7% in the whole MN. Regarding the dependence on B, the asymptotic analysis of Ramos et al [33] for the electron population at the downstream end of the nozzle, yielded nT e u ∝ B and nT e⊥ u ∝ B 5/3 , which is confirmed here. Additionally, it is found here that similar scaling laws apply to the parallel and perpendicular heat fluxes: q e ∝ B and q e⊥ ∝ B 5/3 .…”

Section: Iv1 the Equivalent Fluid Modelsupporting

confidence: 84%

“…For instance, the intermediate value α = 7/2, extracted from figure 10(c), o yieldsγ ≈ 1.2, a value close to some experimental evidence [26][27][28][29]39]. Implementing the crude closure (37) in the energy equation (33) yields the known law between the electric potential fall and the polytropic coefficient, [34] e|φ…”

Section: Iv2 Electron Heat Fluxessupporting

confidence: 69%

“…These laws are important for quick estimates of a MN performance without determining the full plasma response. Ramos et al [33] carried out an analytical study of the asymptotic downstream response except for the heat fluxes.…”

Section: Introductionmentioning

confidence: 99%

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Macroscopic and parametric study of a kinetic plasma expansion in a paraxial magnetic nozzle

Ahedo

Correyero

Navarro-Cavallé

et al. 2020

Plasma Sources Sci. Technol.

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A kinetic paraxial model of a collisionless plasma stationary expansion in a convergent-divergent magnetic nozzle is analyzed. Monoenergetic and Maxwellian velocity distribution functions of upstream ions are compared, leading to differences in the expansion only on second and higher-order velocity moments. Individual and collective magnetic mirror effects are analyzed. Collective ones are small on the electron population since only a weak temperature anisotropy develops, but they are significant on the ions all over the nozzle. Momentum and energy equations for ions and electrons are assessed based on the kinetic solution. The ion response is different in the hot and cold limits, with the anisotropic pressure tensor being relevant in the first case. Heat fluxes of parallel and perpendicular energies have a dominant role in the electron energy equations. They do not fulfill a Fourier-type law; they are large even when electrons are near isothermal. A crude electron fluid closure based on a constant diffusion-to-convective thermal energy ratio is shown equivalent to the much invoked polytropic law. Analytical dimensionless parameter laws are derived for the nozzle total electric potential fall and the downstream residual electron temperature. Electron confinement and related current control by a thin Debye sheath and a the semi-infinite divergent magnetic nozzle are compared.

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Section: Iv1 the Equivalent Fluid Modelsupporting

confidence: 84%

Section: Iv2 Electron Heat Fluxessupporting

confidence: 69%

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Macroscopic and parametric study of a kinetic plasma expansion in a paraxial magnetic nozzle

Ahedo

Correyero

Navarro-Cavallé

et al. 2020

Plasma Sources Sci. Technol.

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“…Third, the electron temperature at the source is assumed isotropic, which is not the situation expected in an ECR thruster. Theoretical work is underway to cancel or at least reduce these model restrictions [34,[36][37][38] IV.2 Fitting of experimental data along the MN of the PM thruster…”

Section: Resultsmentioning

confidence: 99%

Plasma beam characterization along the magnetic nozzle of an ECR thruster

Correyero¹,

Jarrige²,

Packan³

et al. 2019

Plasma Sources Sci. Technol.

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Experimental characterization of plasma properties along the magnetic nozzle of an Electron Cyclotron Resonance thruster is presented here. A permanent magnet prototype and a solenoid prototype are tested, whose main difference relies on the magnetic field strength and topology. A cylindrical Langmuir probe is used to measure plasma potential, plasma density and electron temperature. In the permanent magnet thruster setup , a Laser Induced Fluorescence diagnostics is performed simultaneously with the Langmuir probe to measure the mean ion kinetic energy, and a Faraday gridded probe to characterize the angular plasma beam. An effective electron cooling rate has been identified, as well as the dependence of the total plasma potential drop with the mass flow rate. Results are compared with a supersonic collisionless fluid-kinetic 1D model where electron dynamics account for magnetic mirror effects and potential barriers, while ions are treated as a fluid cold species. The comparison allows to estimate the sonic transition of the plasma flow.

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“…Subramaniam and Raja [6] have considered the simulation of axisymmetric flows of plasmas with application to spacecraft thrusters. Several simulation studies based on numerical codes such as the one by Ahedo et al [7], Ramos, Merino and Ahedo [8] , Lorzel, and Mikellides [9] and Domínguez-Vázquez et al [10] have also been reported. On the experimental side, Qin et al [11,12] have investigated, both in Hall type and Ion thrusters, unstable discharge phenomenon in which discharge voltage oscillations appear, particularly at high discharge currents or low flow rate conditions.…”

Section: Introductionmentioning

confidence: 99%

Feedback control of a spacecraft electro-dynamic thruster

Vepa

2020

Acta Astronautica

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In this paper, the possibility of feedback servo control of a spacecraft thruster's specific impulse by a boundary feedback system is theoretically considered. The motivation to introduce feedback control is two-fold. The first is to stabilize any inherent plasma instabilities and the second is regulate the output specific impulse of the thruster. Two cases are considered: Electro-thermal thrusters and Electro-dynamic thrusters. The chamber inlet temperature in the case of the electro-thermal thruster or the boundary electric field potential responsible for generation of the velocity of the plasma ions in the case of an electrodynamic thruster, are controlled by feedback so as to regulate the thruster's specific impulse. By introducing typical disturbances in the plasma ionization voltage, it is shown using a two-dimensional fluid model and a suitable boundary feedback law, where the chamber inlet temperature or applied boundary potential is proportional to the error in the specific impulse and the desired specific impulse, that the specific impulse of the thruster may be regulated and held constant. The robustness of the control system is numerically tested, by a two dimensional simulation model using McCormacks's method. The Navier-Stockes equations, including the magneto-hydrodynamic variables were discretized and simulated, using the explicit MacCormack method for a typical nozzle domain. The numerical results for the open and closed-loop velocity fields were obtained and the specific impulse was computed from these fields. It was thus shown that not only the stability of the plasma is realised but also that the specific impulse is regulated as desired.

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Three dimensional fluid-kinetic model of a magnetically guided plasma jet

Cited by 17 publications

References 38 publications

Macroscopic and parametric study of a kinetic plasma expansion in a paraxial magnetic nozzle

Macroscopic and parametric study of a kinetic plasma expansion in a paraxial magnetic nozzle

Plasma beam characterization along the magnetic nozzle of an ECR thruster

Feedback control of a spacecraft electro-dynamic thruster

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