A Short Review of Experimental and Computational Diagnostics for Radiofrequency Plasma Micro-thrusters


Experimental and computational diagnostics for radiofrequency plasma micro-thrusters are presented, based on the low power (10–100 W) electrothermal thruster prototype, Mini Pocket Rocket, developed for use on the Cubesat nanosatellite platform. Computer simulations include computer fluid dynamics simulations and particle in cell simulations while experimental results are obtained using a variety of electrostatic, optical and momentum probes. The output and limitations of each diagnostic are discussed within the context of device development for space use.

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  1. 1.

    Goebel DM, Katz I (2008) Fundamentals of electric propulsion: ion and Hall thrusters. Wiley, London

    Google Scholar 

  2. 2.

    Sankaran RM, Giapis KP (2001) Maskless etching of silicon using patterned microdischarges. Appl Phys Lett 79:593–595

    Article  CAS  Google Scholar 

  3. 3.

    Cao Z, Walsh JL, Kong MG (2009) Atmospheric plasma jet array in parallel electric and gas flow fields for three-dimensional surface treatment. Appl Phys Lett 94:021501

    Article  Google Scholar 

  4. 4.

    Charles C, Boswell RW, Bish A (2014) Low-weight fixed ceramic capacitor impedance matching system for an electrothermal plasma microthruster. J Propuls Power 30(4):1117–1121

    Article  Google Scholar 

  5. 5.

    Charles C, Hawkins R, Boswell RW (2015) Particle in cell simulation of a radiofrequency plasma jet expanding in vacuum. Appl Phys Lett 106:093502

    Article  Google Scholar 

  6. 6.

    Greig A, Charles C, Paulin N, Boswell RW (2014) Volume and surface propellant heating in an electrothermal radio-frequency plasma micro-thruster. Appl Phys Lett 105:054102

    Article  Google Scholar 

  7. 7.

    Charles C, Boswell RW (2012) Measurement and modeling of a radiofrequency micro-thruster. Plasma Sources Sci Technol 21:022002

    Article  Google Scholar 

  8. 8.

    Dixon S, Charles C, Boswell R (2013) Spatial evolution of eepfs in a millimetre scale radio frequency argon plume. J Phys D Appl Phys 46(36):365202

    Article  Google Scholar 

  9. 9.

    Greig A, Charles C, Boswell RW (2015) Simulation of main plasma parameters of a cylindrical asymmetric capacitively coupled plasma micro-thruster using computational fluid dynamics. Front Phys 2(80):1–9

    Google Scholar 

  10. 10.

    Gottscho RA, Donnelly VM (1984) Optical emission actinometry and spectral line shapes in rf glow discharges. J Appl Phys 56(2):245–250

    Article  CAS  Google Scholar 

  11. 11.

    Phillips DM (1976) Determination of gas temperature from unresolved bands in the spectrum from a nitrogen discharge. J Phys D Appl Phys 9(3):507

    Article  CAS  Google Scholar 

  12. 12.

    Bruggeman PJ, Sadeghi N, Schram DC, Linss V (2014) Gas temperature determination from rotational lines in non-equilibrium plasmas: a review. Plasma Sources Sci Technol 23(2):023001

    Article  Google Scholar 

  13. 13.

    Poirier J-S, Brub P-M, Muoz J, Margot J, Stafford L, Chaker M (2011) On the validity of neutral gas temperature by N2 rovibrational spectroscopy in low-pressure inductively coupled plasmas. Plasma Sources Sci Technol 20(3):035016

    Article  Google Scholar 

  14. 14.

    Bak MS, Kim W, Cappelli MA (2011) On the quenching of excited electronic states of molecular nitrogen in nanosecond pulsed discharges in atmospheric pressure air. Appl Phys Lett 98(1):011502

    Article  Google Scholar 

  15. 15.

    Bai Bo, Sawin Herbert H, Cruden Brett A (2006) Neutral gas temperature measurements of high-power-density fluorocarbon plasmas by fitting swan bands of c2 molecules. J Appl Phys 99(1):013308

  16. 16.

    Moon SY, Choe W (2003) A comparative study of rotational temperatures using diatomic OH, O2 and N2+ molecular spectra emitted from atmospheric plasmas. Spectrochim Acta Part B At Spectrosc 58(2):249–257

    Article  Google Scholar 

  17. 17.

    Huang X-J, Xin Y, Yang L, Yuan Q-H (2008) Spectroscopic study on rotational and vibrational temperature of N2 and N2+ in dual-frequency capacitively coupled plasma. Phys Plasmas 15:113504

    Article  Google Scholar 

  18. 18.

    Takahashi T, Takao Y, Eriguchi K, Ono K (2009) Numerical and experimental study of microwave-excited microplasma and micronozzle flow for a microplasma thruster. Phys Plasmas (1994-present) 16:083505

    Article  Google Scholar 

  19. 19.

    Fishburne ES (1967) Transfer of electronic energy between a metastable argon atom and a nitrogen molecule. J Chem Phys 47(1):58–63

    Article  CAS  Google Scholar 

  20. 20.

    Greig A, Charles C, Hawkins R, Boswell RW (2013) Direct measurement of neutral gas heating in a radio-frequency electrothermal plasma micro-thruster. Appl Phys Lett 103:074101

    Article  Google Scholar 

  21. 21.

    Dunham JL (1932) The energy levels of a rotating vibrator. Phys Rev 41:721–731

    Article  CAS  Google Scholar 

  22. 22.

    Zare RN, Larsson EO, Berg RA (1965) Franck-condon factors for electronic band systems of molecular nitrogen. J Mol Spectrosc 15(2):117–139

    Article  CAS  Google Scholar 

  23. 23.

    Herzberg G, Huber KP (1945) Molecular spectra and molecular structure. Prentice-Hall, Inc, Englewood Cliffs

    Google Scholar 

  24. 24.

    Gans T, O’Connell D, Schulz-von der Gathen V, Waskoenig J (2010) The challenge of revealing and tailoring the dynamics of radio-frequency plasmas. Plasma Sources Sci Technol 19(3):034010

    Article  Google Scholar 

  25. 25.

    Boffard JB, Lin CC, De Joseph CA Jr (2004) Application of excitation cross sections to optical plasma diagnostics. J Phys D Appl Phys 37(12):R143

    Article  CAS  Google Scholar 

  26. 26.

    Niemi K, Reuter S, Graham LM, Waskoenig J, Knake N, Schulz-von der Gathen V, Gans T (2010) Diagnostic based modelling of radio-frequency driven atmospheric pressure plasmas. J Phys D Appl Phys 43(12):124006

    Article  Google Scholar 

  27. 27.

    Bruneau B, Gans T, O’Connell D, Greb A, Johnson EV, Booth J-P (2015) Strong ionization asymmetry in a geometrically symmetric radio frequency capacitively coupled plasma induced by sawtooth voltage waveforms. Phys Rev Lett 114:125002

    Article  Google Scholar 

  28. 28.

    Charles C, Dedrick J, Boswell RW, O’Connell D, Gans T (2013) Nanosecond optical imaging spectroscopy of an electrothermal radiofrequency plasma thruster plume. Appl Phys Lett 103(12):124103

    Article  Google Scholar 

  29. 29.

    Lazzaroni C, Chabert P, Rousseau A, Sadeghi N (2010) The excitation structure in a micro-hollow cathode discharge in the normal regime at medium argon pressure. J Phys D Appl Phys 43(12):124008

    Article  Google Scholar 

  30. 30.

    Dixon S, Charles C, Boswell R, Cox W, Holland J, Gottscho R (2013) Interactions between arrayed hollow cathodes. J Phys D Appl Phys 46(14):145204

    Article  Google Scholar 

  31. 31.

    Lafleur T, Takahashi K, Charles C, Boswell RW (2011) Direct thrust measurements and modelling of a radio-frequency expanding plasma thruster. Phys Plasmas 18:080701

    Article  Google Scholar 

  32. 32.

    Charles C, Boswell RW, Bish A, Khayms V, Scholz E (2015) Direct measurement of axial momentum imparted by an electrothermal radiofrequency plasma micro-thruster. Submitted to Plasma Sources Sci Technol

  33. 33.

    Lieberman MA, Lichtenberg AJ (2005) Principles of plasma discharges and plasma processing. Wiley, London

    Google Scholar 

  34. 34.

    Murphy HR, Miller DR (1984) Effects of nozzle geometry on kinetics in free-jet expansions. J Phys Chem 88(20):4474–4478

    Article  CAS  Google Scholar 

  35. 35.

    Kolobov VI (2003) Fokker–planck modeling of electron kinetics in plasmas and semiconductors. Comput Mater Sci 28(2):302–320

    Article  CAS  Google Scholar 

  36. 36.

    Lu Y, Yan D, Chen Y (2009) 2-D fluid simulation of dual-frequency capacitively coupled plasma. J Hydrodyn Ser B 21(6):814–819

    Article  Google Scholar 

  37. 37.

    Sheridan TE (2000) How big is a small langmuir probe? Phys Plasmas 7(7):3084–3088

    Article  CAS  Google Scholar 

  38. 38.

    Lafleur T, Boswell RW, Booth JP (2012) Enhanced sheath heating in capacitively coupled discharges due to non-sinusoidal voltage waveforms. Appl Phys Lett 100(19):194101

    Article  Google Scholar 

  39. 39.

    Lafleur T, Boswell RW (2012) Particle-in-cell simulations of hollow cathode enhanced capacitively coupled radio frequency discharges. Phys Plasmas 19(2):023508

    Article  Google Scholar 

  40. 40.

    Baalrud SD, Lafleur T, Boswell RW, Charles C (2011) Particle-in-cell simulations of a current-free double layer. Phys Plasmas 18:063502

    Article  Google Scholar 

  41. 41.

    Meige A, Boswell RW, Charles C, Turner MM (2005) One-dimensional particle-in-cell simulation of a current-free double layer in an expanding plasma. Phys Plasmas 12:052317

    Article  Google Scholar 

  42. 42.

    Dixon S, Charles C, Dedrick J, Gans T, O’Connell D, Boswell R (2014) Observations of a mode transition in a hydrogen hollow cathode discharge using phase resolved optical emission spectroscopy. Appl Phys Lett 105:014104

    Article  Google Scholar 

  43. 43.

    Fruchtman A (2008) Energizing and depletion of neutrals by a collisional plasma. Plasma Sources Sci Technol 17(2):024016

    Article  Google Scholar 

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This research was funded by the Australian Research Council Discovery Projects DP 1096653 and DP140100571 and by the Australian Space Research Program (‘Australian Plasma Thruster’ project with thanks to Jai Vennik for Fig. 5). The original Particle In Cell code written by Dr. Trevor Lafleur was rewritten and modified for the present study by Rhys Hawkins at ANU Supercomputer Facility as part of the ARC DP1096653 project. This project also partially supported the visit by Prof. Timo Gans and Dr. Deborah O’Connor (fast imaging testing campaign of Pocket Rocket at the ANU Space Plasma, Power and Propulsion Laboratory in January/February 2012) and we thank both collaborators for useful discussions. Sects. 4 and 8 were written by Amelia Greig and Sect. 7 was written by Teck Seng Ho.

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Charles, C., Bish, A., Boswell, R.W. et al. A Short Review of Experimental and Computational Diagnostics for Radiofrequency Plasma Micro-thrusters. Plasma Chem Plasma Process 36, 29–44 (2016). https://doi.org/10.1007/s11090-015-9654-5

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  • Micro-thruster
  • Radiofrequency
  • Diagnostics
  • Plasma