We developed a global model aiming to study discharges in CO2 under various conditions, pertaining to a large spectrum of\npressure, absorbed energy, and feeding values. Various physical conditions and form factors have been investigated. The model\nwas applied to a case of radiofrequency discharge and to helicon type devices functioning in low and high feed conditions. In\ngeneral, main charged species were found to be CO2\n+ for sufficiently low pressure cases and O? for higher pressure ones, followed\nby CO2\n+, CO+, andO2\n+ in the latter case.Dominant reaction is dissociation of CO2 resulting into COproduction. Electronegativity,\nimportant for radiofrequency discharges, increases with pressure, arriving up to 3 for high flow rates for absorbed power of 250W,\nand diminishes with increasing absorbed power. Model results pertaining to radiofrequency type plasma discharges are found in\nsatisfactory agreement with those available from an existing experiment. Application to low and high flow rates feedings cases of\nhelicon thruster allowed for evaluation of thruster functioning conditions pertaining to absorbed powers from50Wto 1.8kW.The\nmodel allows for a detailed evaluation of the CO2 potential to be used as propellant in electric propulsion devices.
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