Investigation of free-floating resonant cavity microwave plasmas forpropulsion

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

Results of experiments with high-pressure helium and nitrogen discharges generated in a microwave resonant cavity for use in an electrothermal thruster are presented. The cavity, operating in the TMoii mode, generated the discharges within a quartz sphere, which allowed the discharge to be both free floating and away from solid surfaces. Input powers of up to 400 W were used with gas pressures up to 300 kPa (absolute) and mass flow rates up to 2.79 x 10 4 kg/s. Coupling efficiencies up to 19% have been demonstrated, and temperature measurements 200 mm downstream of the plasma indicate thermal efficiencies of up to 36.6% and total efficiencies of up to 25.2%, both increasing linearly with mass flow rate. The downstream temperature measurements also closely match the coupling efficiency behavior when plotted against pressure. Absolute measurements of the continuum radiation yield electron temperatures of between 10,200 and 10,900 K, which are insensitive to changes in the operating conditions.

Original languageEnglish (US)
Pages (from-to)103-109
Number of pages7
JournalJournal of Propulsion and Power
Volume8
Issue number1
DOIs
StatePublished - Jan 1 1992

Fingerprint

Cavity resonators
cavity resonators
floating
cavity
mass flow rate
Microwaves
Plasmas
plasma
microwaves
temperature measurement
Temperature measurement
thermodynamic efficiency
temperature
Flow rate
solid surfaces
helium
gas pressure
Electron temperature
quartz
electron energy

All Science Journal Classification (ASJC) codes

  • Aerospace Engineering
  • Fuel Technology
  • Mechanical Engineering
  • Space and Planetary Science

Cite this

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title = "Investigation of free-floating resonant cavity microwave plasmas forpropulsion",
abstract = "Results of experiments with high-pressure helium and nitrogen discharges generated in a microwave resonant cavity for use in an electrothermal thruster are presented. The cavity, operating in the TMoii mode, generated the discharges within a quartz sphere, which allowed the discharge to be both free floating and away from solid surfaces. Input powers of up to 400 W were used with gas pressures up to 300 kPa (absolute) and mass flow rates up to 2.79 x 10 4 kg/s. Coupling efficiencies up to 19{\%} have been demonstrated, and temperature measurements 200 mm downstream of the plasma indicate thermal efficiencies of up to 36.6{\%} and total efficiencies of up to 25.2{\%}, both increasing linearly with mass flow rate. The downstream temperature measurements also closely match the coupling efficiency behavior when plotted against pressure. Absolute measurements of the continuum radiation yield electron temperatures of between 10,200 and 10,900 K, which are insensitive to changes in the operating conditions.",
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Investigation of free-floating resonant cavity microwave plasmas forpropulsion. / Balaam, Phil; Micci, Michael Matthew.

In: Journal of Propulsion and Power, Vol. 8, No. 1, 01.01.1992, p. 103-109.

Research output: Contribution to journalArticle

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