Particle Simulations of Ion Generation and Transport in Microelectromechanical Systems and Micropropulsion

By Venkattraman Ayyaswamy

Aeronautics & Astronautics, Purdue University, West Lafayette, IN

Published on

Abstract

Field emission/ionization is the process of electron/ion generation due to intense electric fields. This work presents a particle-based computational approach using the particle-in-cell (PIC) and the direct simulation Monte Carlo (DSMC) methods to study ion generation and transport in microelectromechanical systems (MEMS) and micropropulsion. In particular, the effects of field emission and field ionization due to intense electric fields are studied in detail. Electrostatically actuated MEMS devices such as switches, filters, resonators use significant voltage bias across micron-sized gaps resulting in electric fields > 107 V/m. The resulting electron emission from the cathode has important implications on reliability and performance of such devices. The first part of the talk deals with use of the PIC method with Monte Carlo collisions (MCC) between electrons and the ambient neutral gas to develop models to predict charge accumulation, breakdown voltage, etc. for various ambient gases, gap sizes, cathode material, and frequency of applied voltage. The second part deals with the modeling of field emission ion thrusters which are low thrust/high specific impulse devices used for in-space propulsion. The thrust is generated by extracting ions from a metallic liquid surface and accelerating them through a few kV potential difference. Particle simulations used to predict performance parameters of these thrusters are validated using experimental data for the current distribution.

Bio

Venkattraman Ayyaswamy Venkattraman Ayyaswamy received his BS in Aerospace Engineering in 2007 from the Indian Institute of Technology Madras, India. He got his MS in Aeronautics & Astronautics, with a specialization in computational engineering from Purdue in 2009. His main research interests are in theoretical and computational nonequilibrium flows including plasma physics During his graduate school he has worked with his advisor Prof. Alina Alexeenko, on several problems in diverse applications such as MEMS, vacuum technology, and hypersonic flows. Venkattraman was also a summer student in 2010 at the Lawrence Livermore National Laboratory (LLNL) working on 3D plasma simulations for the National Ignition Facility (NIF)

Cite this work

Researchers should cite this work as follows:

  • Venkattraman Ayyaswamy (2012), "Particle Simulations of Ion Generation and Transport in Microelectromechanical Systems and Micropropulsion," https://nanohub.org/resources/14112.

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Location

Lawson Computer Science Building, Room 3102, Purdue University, West Lafayette, IN

Tags

Particle Simulations of Ion Generation and Transport in Microelectromechanical Systems and Micropropulsion
  • Particle Simulations of Ion Generation and Transport in Microelectromechanical Systems and Micropropulsion 1. Particle Simulations of Ion Ge… 0
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  • Outline 2. Outline 31.133333333333333
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  • Introduction 3. Introduction 76.63333333333334
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  • Background & Motivation: MEMS 4. Background & Motivation: MEMS 244.2
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  • Background & Motivation: MEMS 5. Background & Motivation: MEMS 330.26666666666665
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  • Breakdown in Microgaps: Field Emission 6. Breakdown in Microgaps: Field … 449.56666666666666
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  • Goals & Objectives 7. Goals & Objectives 650.9
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  • Outline 8. Outline 720.8
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  • Numerical Methods: Particle-in-cell/Monte Carlo Collisions 9. Numerical Methods: Particle-in… 736.06666666666672
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  • Outline 10. Outline 828.83333333333337
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  • PIC/MCC Simulations of Microdischarges 11. PIC/MCC Simulations of Microdi… 848.9
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  • Mathematical Models for Modified Paschen Curve 12. Mathematical Models for Modifi… 978.16666666666663
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  • Determining Ionization Coefficient 13. Determining Ionization Coeffic… 1069.1
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  • Determining Ionization Coefficient 14. Determining Ionization Coeffic… 1255.8666666666666
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  • Ionization Coefficient Dependence on Gap Size 15. Ionization Coefficient Depende… 1340.4666666666667
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  • Dependence of Ap and Bp on Gap Size. 16. Dependence of Ap and Bp on Gap… 1429.7666666666667
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  • Field Emission: Current Measurements 17. Field Emission: Current Measur… 1537.2333333333334
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  • Determining Ion-Enhancement Coefficient 18. Determining Ion-Enhancement Co… 1625.8
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  • Current Density with Ion-Enhancement 19. Current Density with Ion-Enhan… 1651.4333333333334
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  • Model for Ion-Enhancement Coefficient 20. Model for Ion-Enhancement Coef… 1748.2666666666667
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  • Breakdown Model based on PIC/MCC Simulations 21. Breakdown Model based on PIC/M… 1806.6
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  • Outline 22. Outline 1867.2333333333334
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  • Motivation: Micropropulsion 23. Motivation: Micropropulsion 1883.8333333333333
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  • Field Emission Electric Propulsion (FEEP) 24. Field Emission Electric Propul… 1929.8666666666666
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  • FEEP: Previous Work 25. FEEP: Previous Work 1995.0666666666666
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  • Challenges in Multiphysics Simulations 26. Challenges in Multiphysics Sim… 2038.5666666666666
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  • PIC Simulations of a FEEP Microthruster 27. PIC Simulations of a FEEP Micr… 2071.1
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  • Preliminary Results 28. Preliminary Results 2122.7
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  • Current Reconstruction Algorithm 29. Current Reconstruction Algorit… 2175.9333333333334
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  • Comparison with Measurements 30. Comparison with Measurements 2193.1333333333332
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  • Comparison with Measurements 31. Comparison with Measurements 2253.9333333333334
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  • Conclusions 32. Conclusions 2305.6666666666665
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  • QUESTIONS ? 33. QUESTIONS ? 2374.7
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