Electron property measurements made by Langmuir probes and laser Thomson scattering have been compared in weakly magnetized plasma conditions using a planar unbalanced magnetron with the aim of assessing the accuracy of the probe diagnostic. The measurements were performed at several locations within the magnetic field configuration, the magnetic null region ( mT) on the discharge axis and inside the last closed flux surface boundary with fields up to 33 mT. There was good diagnostic agreement during High Power Impulse Magnetron Sputtering, but significant discrepancies were observed for DC magnetron operation, even at the magnetic null. For some discharge conditions, the electron density determined by Thomson scattering was over an order of magnitude greater than the plasma density obtained from the Langmuir probe, using both ion and electron collection theories. In addition, the low energy part of the electron energy distribution function determined by the probe was depleted. The possible reasons for the discrepancies are discussed, with the conclusion being that the plasma was significantly perturbed by the probe stem. The range of plasma densities and electron temperatures measured in this study were 0.4–54 × 1017 m−3 and 0.2–5.9 eV, respectively.
Skip Nav Destination
Article navigation
July 2019
Research Article|
July 29 2019
Comparison of Langmuir probe and laser Thomson scattering for electron property measurements in magnetron discharges
Peter J. Ryan
;
Peter J. Ryan
a)
Department of Electrical Engineering and Electronics, University of Liverpool
, Brownlow Hill, Liverpool L69 3GJ, United Kingdom
Search for other works by this author on:
James W. Bradley
;
James W. Bradley
Department of Electrical Engineering and Electronics, University of Liverpool
, Brownlow Hill, Liverpool L69 3GJ, United Kingdom
Search for other works by this author on:
Mark D. Bowden
Mark D. Bowden
Department of Electrical Engineering and Electronics, University of Liverpool
, Brownlow Hill, Liverpool L69 3GJ, United Kingdom
Search for other works by this author on:
a)
Electronic mail: ryanp@liverpool.ac.uk
Phys. Plasmas 26, 073515 (2019)
Article history
Received:
May 10 2019
Accepted:
June 26 2019
Citation
Peter J. Ryan, James W. Bradley, Mark D. Bowden; Comparison of Langmuir probe and laser Thomson scattering for electron property measurements in magnetron discharges. Phys. Plasmas 1 July 2019; 26 (7): 073515. https://doi.org/10.1063/1.5109621
Download citation file:
Sign in
Don't already have an account? Register
Sign In
You could not be signed in. Please check your credentials and make sure you have an active account and try again.
Pay-Per-View Access
$40.00
Citing articles via
ICF target optimization using generative AI
M. Ben Tayeb, V. Tikhonchuk, et al.
The long road to ignition: An eyewitness account
Mordecai D. Rosen
Progress toward fusion energy breakeven and gain as measured against the Lawson criterion
Samuel E. Wurzel, Scott C. Hsu
Related Content
Comparison of Langmuir probe and laser Thomson scattering for plasma density and electron temperature measurements in HiPIMS plasma
Phys. Plasmas (April 2019)
On the electron energy in the high power impulse magnetron sputtering discharge
J. Appl. Phys. (June 2009)
Investigation of reliability of the cutoff probe by a comparison with Thomson scattering in high density processing plasmas
Phys. Plasmas (December 2017)
Comparison of electron property measurements in an inductively coupled plasma made by Langmuir probe and laser Thomson scattering techniques
J. Vac. Sci. Technol. A (March 1999)
Reproducibility of the cutoff probe for the measurement of electron density
Phys. Plasmas (June 2016)