7th Asia-Pacific Conference on Plasma Physics, 12-17 Nov, 2023 at Port Messe Nagoya

Research Activities at the Magnetised Plasma Interaction Experimental FacilityCormac Corr1
1Department of Materials Physics, Research School of Physics, Australian National University
e-mail (speaker): cormac.corr@anu.edu.auHigh density hydrogen plasma sources in the presence ofa magnetic field are of importance to several areas such as
material processing, studying fusion-relevant plasmasurface interactions, developing neutral beam injection
systems, and plasma propulsion. Helicon coupled plasmas
have been proposed as a possible design alternative tocurrent ICP systems as a negative source for neutral beam
injection systems due to lower RF power. Helicon plasmas
can obtain higher plasma densities by an order ofmagnitude and achieve higher nH /nH2 ratios compared toICP systems for the same RF power; are able to generate
stable plasmas at lower pressures; and do not require
extensive re-design of current source designs. Most
studies on helicon-based plasmas have focused on lower
power operation of less than 2 kW.
The MAGnetised Plasma Interaction Experiment(MAGPIE) at the Australian National University (ANU)
is a high-power helicon plasma device operating at RFpowers up to 20 kW. The magnetic field configuration ofMAGPIE is versatile and can provide both magneticmirror and diverging field configurations. To date, manyof the studies on MAGPIE have been carried out with themagnetic mirror configuration. High plasma densities of afew 1019 m−3 have been achieved with relatively low
electron temperatures (< 8eV) at low pressures (<10mTorr). An example of spatially resolved electron
densities and temperature in MAGPIE is shown inFigure 1 when operating with a magnetic mirror.
This contribution will combine several studies on gas
heating, plasma chemistry, negative ion dynamics andneutral depletion [1-8]. The plasma is diagnosed usingprobe-based laser photodetachment, Langmuir probes,
laser induced fluorescence, cavity ringdown spectroscopy,
mass spectroscopy and optical emission spectroscopy.
The experimental results are compared and validated withboth a zero-dimensional global model and a 2D
axisymmetric model. This presentation will provide an
overview of research conducted at the MAGPIE facility
on negative ion production, plasma-material interaction
studies and plasma torches.

Figure 1. Spatially resolved electron density andtemperature in a hydrogen plasma operating at 10mTorr,
20 kW with a magnetic mirror.
References[1] B.D. Blackwell, J.F. Caneses, C.M. Samuell, J. Wach,J. Howard and C.S. Corr, “Design and characterization of
the Magnetized Plasma Interaction Experiment(MAGPIE): a new source for plasma-material interaction
studies”, Plasma Sources Sci. Technol. 21 (2012) 055033[2] C.M. Samuell and C.S. Corr, “Atomic and molecularhydrogen gas temperatures in a low-pressure heliconplasma”, Plasma Sources Science and Technology 24(2015) 045003[3] J. Santoso, R. Manoharan, S. O'Byrne, and C. Corr,“Negative hydrogen ion production in a helicon plasmasource”, Physics of Plasmas 22, 093513 (2015)[4] C. Samuell and C. Corr, “Low-pressure hydrogenplasmas explored using a global model", Plasma Sources
Sci. Technol. 25 (2016) 015014[5] J. Santoso, H. V. Willett, C. S. Corr “High density
negative hydrogen ion production in a high power pulsed
helicon discharge”, Plasma Sources Sci. Technol. 2710LT03[6] Samuel Cousens, Jesse Santoso, Cormac S. Corr,“Depletion of atomic hydrogen in a high power helicondischarge”, (2020) Plasma Sources Sci. Technol. 29
11LT01[7] T. Lafleur and C. S. Corr, “Characterization of aradio-frequency inductively coupled electrothermal
plasma thruster” J. Appl. Phys. 130, 043304 (2021)[8] A. Pascal, T. LaFleur, C.S. Corr, “Bidirectionalvortex stabilization of a supersonic inductively coupledplasma torch” J. Phys. D: Appl. Phys. 56 (2023) 105202