Computational Study of Primary Electron Confinement by Magnetic Fields in the  Discharge Chamber of an Ion Engine

Mahalingam, Sudhakar; Menart, James

doi:10.2514/1.18366

Cited by 10 publications

(8 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As the results show in figure 4, there is no significant difference in the magnetic-field distributions of the three discharge chamber structures. The green line in figure 4 is the 50 Gs magneticfield isopotential, and the region enclosed by this line is called the 'magnetic-field free area' [13]. The magnetic field in this region has less of an effect on the plasma than the magnetic field near the anode, and the larger the volume of the 'free area', the better the flatness of the ion beam.…”

Section: Simulation Results and Analysismentioning

confidence: 99%

“…As shown in figure 2(a), the DCM is composed of column and cone structures, which are all made of tantalum material due to the small thermal deformation of titanium at high temperatures. The radius of the discharge chamber outlet, also the screen grid radius, is 0.143 m. Four annular magnets made of permanent magnetic material form a ringcusp field, which makes the discharge process more uniform [12,13]. Middle magnet 2 is nearly mounted in the middle of the cone structure, and the downstream magnet is installed at the bottom of the discharge chamber.…”

Section: Discharge Model and Boundary Settingsmentioning

confidence: 99%

See 1 more Smart Citation

A study of the influence of different grid structures on plasma characteristics in the discharge chamber of an ion thruster

Sun¹,

Long²,

Guo³

et al. 2022

Plasma Sci. Technol.

View full text Add to dashboard Cite

The grid structure has significant effects on the discharge characteristics of ion thruster. The discharge performances of 30 cm diameter ion thruster with flat, convex and concave grids are studied. The analysis results show that the discharge chamber with a convex grid has a larger “magnetic field free area” than others, and the parallelism of magnetic field isopotential lines and anode is basically same in the three models. Plasma densities of the three structures at the grid outlet are in the range of 3.1×1016‒6.9×1017 m−3. Along the thruster axis direction, the electron temperature in the chamber with convex and concave grid is in the range of 3.3‒3.5 eV, while that with a flat grid is lower, in the range of 3.1‒3.5 eV. In addition, the convex grid and the concave grid have better uniform distribution of electron temperature. Moreover, the collision frequency ratios show that axial ionization degree of the three models is the highest, and the flat grid has the highest discharge efficiency, then the convex grid, and the concave grid is the worst. The test and simulation results of 30 cm diameter ion thruster with convex grid show that the measurement and calculation results are 3.67 A and 3.44 A respectively, and the error above mainly comes from the ignorance of the double charged ions and parameter setting in the model. The comparison error between simulation and measurement of beam current density is mainly caused by the actual thermal deformation of the grids during the discharge process, which leads to the change of electric potential distribution and the variation of focusing characteristics of the grids. With the consideration of discharge performance and the thermal grid gap variation, it can be concluded that the flat and concave grids are more suitable for small diameter ion thrusters, while convex grid is a more reasonable choice for the higher power and larger diameter thrusters.

show abstract

Section: Simulation Results and Analysismentioning

confidence: 99%

Section: Discharge Model and Boundary Settingsmentioning

confidence: 99%

A study of the influence of different grid structures on plasma characteristics in the discharge chamber of an ion thruster

Sun¹,

Long²,

Guo³

et al. 2022

Plasma Sci. Technol.

View full text Add to dashboard Cite

show abstract

“…where i e is the energy of the particle i and Q j i ( ) e is the j-th collision at the cross-section between the particle i and the target particle, j N 1 .   The collision frequency of particle i within a timestep, t, D can be determined by equation (6).…”

Section: Discharge Chamber Modelmentioning

confidence: 99%

“…Hirakawa coupled the ionization process into the model, and, thereafter, calculated the ion loss rate on the wall. To increase the speed of the PIC-MCC model, Mahalingam et al [5,6] increased the vacuum dielectric constant and reduced the mass of heavy particles, therefore realizing the full simulation of the discharge process in the discharge chamber. Wirz et al [7][8][9][10] established a two-dimensional axisymmetric particlefluid mixing model in which the motion of the primary electrons and neutral atoms was calculated by the PIC-MCC and View Factor methods, respectively.…”

Section: Introductionmentioning

confidence: 99%

Numerical simulation of the start-up process of a miniature ion thruster

Yang¹,

Wei²,

Jiang³

et al. 2022

Plasma Sci. Technol.

View full text Add to dashboard Cite

The particle-in-cell Monte Carlo collision model of a discharge chamber is established to investigate the start-up process of a miniature ion thruster. We present the discharge characteristics at different stages (initial stage, development stage, and stable stage) according to the trend of the discharge current with time. The discharge current is the sum of the sidewall current and the backplate current. During the start-up process, the sidewall current lags behind the backplate current. The variation and distribution characteristics of the discharge current over time are determined by the electron density distribution and electric potential distribution.

show abstract

“…17 Previous research efforts with primary electrons have experimentally measured the local cusp density for a 10 cm discharge 18 and computationally improved confinement using a particle tracker. 19 However, their findings are focused on large scale general confinement and do not address the intricate field structures inherent in microdischarges. Recently, researchers have used an analytical analysis using magnetic stream contours to model the plasma conditions within a 3 cm axisymmetric ring cusp discharge.…”

Section: Introductionmentioning

confidence: 99%

Influence of Upstream Field Structure on Primary Electron Loss for a Permanent Magnet Cusp

Dankongkakul

Araki

Wirz

2013

49th AIAA/ASME/SAE/ASEE Joint Propulsion Conference

View full text Add to dashboard Cite

An improved understanding of the electron loss behavior for permanent magnet cusps is needed to enable the design of efficient micro-scale plasma devices. Such devices can be used for a variety of applications, including high performance micro-thrusters that are attractive for primary propulsion for microsatellites, secondary propulsion for larger spacecraft, and formation flying. Conventional plasma loss theory for magnetic cusps generally relates the loss area to an analytical expression related to the magnetic field strength at the loss surface. In contrast, this study examines the importance of the upstream magnetic field structure on the loss behavior of high energy electrons. For the experimental effort, an electron gun is used to inject monoenergetic electrons towards a cusp confined discharge, while precision electron loss measurements are made at the face of a single permanent magnet point cusp. Measurements are taken at facility base pressure and with xenon background gas. A Monte-Carlo model is used to provide detailed examination of the electron confinement and loss behavior. Comparison of the experimental and computational results shows that the primary electron loss behavior is strongly influenced by the upstream magnetic field structure and is not simply dictated by the field strength very near the cusp collection surface. NomenclatureB B Block B Cylind H m L m m M q r = = = = = = = = = magnetic field magnetic field induced by a block magnet magnetic field induced by a cylindrical magnet height of a block magnet length of a magnet mass of an electron magnetization charge location of interestradius of curvature Larmor radius location of the magnet center radius of a magnet curvature drift velocity grad-B drift velocity parallel velocity perpendicular velocity width of a block magnet gradient of the magnetic field

show abstract

Computational Study of Primary Electron Confinement by Magnetic Fields in the Discharge Chamber of an Ion Engine

Cited by 10 publications

References 8 publications

A study of the influence of different grid structures on plasma characteristics in the discharge chamber of an ion thruster

A study of the influence of different grid structures on plasma characteristics in the discharge chamber of an ion thruster

Numerical simulation of the start-up process of a miniature ion thruster

Influence of Upstream Field Structure on Primary Electron Loss for a Permanent Magnet Cusp

Contact Info

Product

Resources

About