ECRIS2012 - List of Authors (Charles, C.)

Paper

Title

Page

Neutral Gas Temperature Measurements of a Radio Frequency Micro-thruster

25

A.D. Greig, R.W. Boswell, C. Charles, R.P. Hawkins
SP3, Canberra, Australia
M.D. Bowden, Y.C. Sutton
The Open University, Milton Keynes, United Kingdom

A radio frequency (13.56 MHz) capacitively coupled cylindrical argon plasma discharge was analysed using optical emission spectroscopy (OES) for various powers and pressures in the ranges 10 W to 40 W and 0.5 Torr to 5 Torr. Trace amounts of nitrogen were added to the discharge to estimate the temperature of the neutrals using rovibrational band matching of the 2^nd positive system of nitrogen and the 1^st negative system of nitrogen ions. Comparing simulated computer generated spectra of these bands to experimentally measured spectra determined the rotational and vibrational temperatures of the nitrogen, from which the temperature of the neutrals was inferred by assuming the rotational temperature was the same as the neutral gas temperature.

Slides TUYO04 [1.341 MB]

WEXO01

Ion Beam Formation in Expanding Plasmas and its Application to Plasma Thrusters

C. Charles
SP3, Canberra, Australia

For the past few decades, Direct Current (DC), radiofrequency (RF) and microwave plasma sources have been used for materials processing, materials diagnostics and electric propulsion in space. When terminated by a series of biased grids on one side, these sources can produce accelerated ion beams (which need to be neutralized) and thrust as shown by successful space missions (e.g. DC Kaufman thruster, RF Artemis thruster and microwave Hayabusa thruster). When open to vacuum or space on one side (no grid or electrode), plasma expansion occurs. The geometric and/or magnetic expansion leads to ion acceleration with sufficient electrons to provide quasi-neutrality. Applying a divergent magnetic field may lead to the spontaneous formation of an electric double layer, a sudden drop of potential within a plasma. In the laboratory, low energy large area ion beams accelerated by current-free double layers produced by RF plasma sources have been created using a variety of gases (Ar, O₂, H₂, CO₂, Xe, Kr, CH₄, NH₃, N₂O) and used in the production of surfaces with a variable degree of hydrophobicity and as a source of thrust in the development of new space engines.

Slides WEXO01 [8.477 MB]

Paper	Title	Page
TUYO04	Neutral Gas Temperature Measurements of a Radio Frequency Micro-thruster	25
	A.D. Greig, R.W. Boswell, C. Charles, R.P. Hawkins SP3, Canberra, Australia M.D. Bowden, Y.C. Sutton The Open University, Milton Keynes, United Kingdom
	A radio frequency (13.56 MHz) capacitively coupled cylindrical argon plasma discharge was analysed using optical emission spectroscopy (OES) for various powers and pressures in the ranges 10 W to 40 W and 0.5 Torr to 5 Torr. Trace amounts of nitrogen were added to the discharge to estimate the temperature of the neutrals using rovibrational band matching of the 2^nd positive system of nitrogen and the 1^st negative system of nitrogen ions. Comparing simulated computer generated spectra of these bands to experimentally measured spectra determined the rotational and vibrational temperatures of the nitrogen, from which the temperature of the neutrals was inferred by assuming the rotational temperature was the same as the neutral gas temperature.
	Slides TUYO04 [1.341 MB]

WEXO01	Ion Beam Formation in Expanding Plasmas and its Application to Plasma Thrusters
	C. Charles SP3, Canberra, Australia
	For the past few decades, Direct Current (DC), radiofrequency (RF) and microwave plasma sources have been used for materials processing, materials diagnostics and electric propulsion in space. When terminated by a series of biased grids on one side, these sources can produce accelerated ion beams (which need to be neutralized) and thrust as shown by successful space missions (e.g. DC Kaufman thruster, RF Artemis thruster and microwave Hayabusa thruster). When open to vacuum or space on one side (no grid or electrode), plasma expansion occurs. The geometric and/or magnetic expansion leads to ion acceleration with sufficient electrons to provide quasi-neutrality. Applying a divergent magnetic field may lead to the spontaneous formation of an electric double layer, a sudden drop of potential within a plasma. In the laboratory, low energy large area ion beams accelerated by current-free double layers produced by RF plasma sources have been created using a variety of gases (Ar, O₂, H₂, CO₂, Xe, Kr, CH₄, NH₃, N₂O) and used in the production of surfaces with a variable degree of hydrophobicity and as a source of thrust in the development of new space engines.
	Slides WEXO01 [8.477 MB]