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The presented study aims to minimize the energy consumed by a Hall effect thruster (HET) under a constraint which makes it possible to generate a specified magnetic field in a target region of the thruster.

Herein topology optimization (TO) is used to reduce the energy consumption of an HET while keeping its performance unchanged. The design variables are the current densities in the coils and the distribution of materials in the polar pieces of the thruster. Intermediate values of material distribution are penalized using the solid isotropic material with penalization method to favor binary solutions. By means of the adjoint method, this paper provides the derivatives of the objective and constraint functions with respect to material distribution and current density variables.

The TO-based design methodology is developed and validated on a design example involving 2,051 variables. The approach shows its interest and its effectiveness of on a large scale two-criteria problem.

In this paper, TO is presented as a tool that has allowed to explore new and innovative designs. However, although the design presented is original, its fabrication is not feasible. Despite this, the designs found give a good idea of the starting points for shape and parametric optimization tools.

Through the HET design problem, TO shows the ability to explore more original design possibilities of a complex magnetostatic design problem and to discover designs that make a HET more efficient with respect to several criteria at the same time.

A new way to reduce the energy consumption of a HET is presented. To achieve this, an adjoint-based TO method is developed and then implemented in a simple way. This approach shows that, for efficiency purposes, TO is a key tool for extending the state of the art of HET designs.

This paper aims to provide an overview of current and historical arcjet development. The reviewed arcjets are considered with respect to both design and thruster relevant parameters. Correspondingly, the paper enables the identification of adequate design criteria and of the probable thruster parameters.

The approach consists of a database for thruster relevant parameters in conjunction with relevant operational requirements (such as type of propellant) and specific design criteria (such as e.g. propellant injection systems).

The synopsis of both operational parameter and respectively assigned design allows for the derivation of development approaches for arcjets under given high level requirements such as power regime.

The paper is a general review. However, its strength is in the synthesis of the arcjet classification, the functional evidence of design criteria and the application scenario.

Not only basic but also specific design criteria are analyzed and evaluated leading to a recommendation feature of the paper with respect to the overall design of adequate arcjets.

Within the scope of the Clean Space initiative, new applications and scenarios from the operation of arcjets arise enabling EOL phases of spacecraft that fulfill respective levels of debris mitigation and, in addition, the requirements concerning the adequately adapted re-entry of spacecrafts that are at end of life.

The paper is a general review. However, its strength is in the synthesis of the arcjet classification, the functional evidence of design criteria and the application scenario.

In magnetostatics, topology optimization (TO) addresses the problem of finding the distributions of both current densities and ferromagnetic materials to comply with fixed magnetic specifications. The purpose of this paper is to develop TO in order to design Hall-effect Thrusters (HETs).

In fact, TO problems are known to be large-scale optimization problems. The authors therefore adopt the adjoint method to reduce the computation time required to obtain the gradient information. In this paper, they illustrate the continuous variant of the adjoint method in the context of magnetostatics TO. Herein, the authors propose an implementation of the adjoint method then use it within a gradient-based optimization solver fmincon-MATLAB to solve a HET TO design problem.

By comparison with finite difference method, the authors validate the accuracy of the suggested implementation of the adjoint method. Then, they solve a large-scale HET TO design problem. The resultant design of TO is distinctly original and not intuitive.

In this paper, the authors introduce TO as a tool that has allowed them to explore new and innovative design of a HET. However, although the design presented is original, its manufacture is not feasible. Thus, a discussion section has been included at the end of paper to suggest a possible way to concretize topological solutions.

TO helps to explore more original design possibilities. In this paper, the authors present an implementation of the adjoint method that makes it possible to solve efficiently and in less central processing unit time large-scale TO design problem.

An easy implementation of the adjoint method is presented in magnetostatics TO. This implementation was first validated by comparison with the finite difference method and then used to solve a large-scale design problem. The result of the TO design problem is distinctly original and non-intuitive.

In this work, the authors deal with topology optimization in electromagnetism using solid isotropic material with penalization (SIMP) method associated with a gradient-based algorithm. The purpose of this study is to propose and investigate the impact of new generalized material interpolation scheme (MIS) used in SIMP approaches.

The variable domains of this kind of electromagnetism design problem are decomposed into small squares which represent a material point (iron here) or void. A least square function where the magnetic field in a target zone has to be as close as possible to a fixed one is minimized. Then the binary optimization problem is relaxed to a continuous one. By using the adjoint variable method, the gradient is provided. By penalizing the objective function using MIS, gradient-based algorithms can then be directly applied to provide efficient solutions close to the binary ones.

In this work, new general MISs are proposed. It is shown on numerous numerical instances that the so-obtained design solutions are more precise to define the zones with or without materials.

Only the linearity of the materials is addressed because the associated adjoint method needs this assumption. However, the new penalization approaches are not dependent directly on this assumption.

The new MISs are efficiently applied to design of a hall effect thruster (HET) magnetic circuits. Furthermore, these schemes are generic and can then be applied to other topology optimization applications in electromagnetism as well as and in mechanism.

Thruster point assembly mechanism (TPAM) of the electric propulsion system allows to adjust the thrust vector, so that the thrust vector is directed to the satellite center of gravity (COG) during the satellite on-orbit working period. In this way the impact of disturbance torque caused by deviation of the thrust vector from the satellite COG during thruster ignition can be decreased. Therefore, the control accuracy of satellite is influenced directly by the control accuracy of TPAM. On the other hand, the on-orbit application of TPAM is restricted to the on-orbit computer resource. Therefore, the purpose of this paper is to design a control strategy for TPAM, and the strategy should not only be able to control the TPAM precisely but also be easily implemented by the on-board computer.

First, the structure and work principle of TPAM are discussed, and the mathematical model based on D-H coordinate system is built for it. Then the fitting methods are utilized to design the control strategy of TPAM. Absolute position fitting-based control strategy and relative position fitting-based control strategy are designed, and the least squares algorithm is introduced for parameter selection.

Simulations and tests are provided for the TPAM. Compared with the state-of-the-art PD controller, the proposed control strategy shows smaller overshoot and more simple realization. The experiment results are matched with the simulation results and both the experiment and simulation results show the validity of the proposed control strategies.

The designed control strategies can be used for the TPAM of some satellite’s electric propulsion system.

The mathematical model of the TPAM based on D-H coordinate system is given. The absolute position fitting-based control strategy and relative position fitting-based control strategy are proposed. Compared with existing methods, the two control strategies have more simple structure and smaller amount of computations. Furthermore, the relative position fitting-based control strategy achieves high precision with simple structure.

For the numerical simulation of magnetoplasmadynamic (MPD) self‐field thruster flow, the solution of one of the two dynamical Maxwell equations – Faraday's law – is required. The Maxwell equations and Ohm's law for plasmas can be summarized in one equation for the stream function so that the two‐dimensional, axisymmetric magnetic field can be calculated. The finite volume (FV) discretization of the equation on unstructured, adaptive meshes is presented in detail and solutions for different thruster currents are shown. The calculated thrust is compared with the experimental data.

The purpose of this paper is to describe the micro fluid flow analysis in a micro thruster of micro‐/nano‐ satellite propulsion system and to propose the algorithm for the fluid flow simulations with the open boundary based on moving boundary method.

The analysis is based on a finite volume moving boundary method. Underlying mathematical model is the system of Navier‐Stokes‐Fourier partial differential equation describing compressible gas model. Propellant under the study is pure nitrogen gas. First, the static geometry velocity vector field is calculated and the information of the velocity at the outflow boundary is obtained; then, with the moving boundary method the outlet boundary is evolved. Evolution of the boundary is stopped when the continuum model ceases to hold. The criteria of the continuum model failure are based on the local Knudsen number.

The validations of the flow with respect to the Knudsen number showed that the continuum model is valid in the nozzle interior part (from the pressure value to the nozzle throat). The exterior nozzle part (diverging side) showed immediate raising of the Knudsen number above the continuum threshold (0.01). For the overall accurate computations of thruster flow, the continuum model must be coupled with molecular model (i.e. Boltzmann BGK).

In this paper, the authors propose a method for the computation of an open boundary flow with the application of the moving boundary method.