Speaker
Viktor Schneider
Description
See the full Abstract at http://ocs.ciemat.es/EPS2018ABS/pdf/P1.3005.pdf
An optically trapped microparticle as plasma probe
V. Schneider, H. Kersten
Institute of Experimental and Applied Physics, Christian-Albrechts-University Kiel, Kiel,
Germany
The idea to use microparticles for plasma diagnostic purposes was implemented during the
last decades by several experiments as electrostatic or thermal probes [1]-[5]. Because of their
small size (µm to nm) microparticles can be used in studies of dynamic processes [6] as well
as single probes in plasma sheath diagnostics [7, 8]. In contrast to common plasma diagnos-
tic tools (e.g. Langmuir probes, calorimetric probes, mass spectrometers etc.), the µPLASMA
(microparticles in a discharge with laser assisted manipulation) experiment [9] uses optically
trapped microparticles (SiO2) as noninvasive single probes. The displacement of the particle in
the laser trap is observed to measure a force while it is moving relatively to the plasma, either
deeper into the sheath or into the plasma bulk. In addition, information about the neutral gas
damping of the particles is presented. Systematic measurements of the residual charges [10]
on the particle after switching off the plasma are performed, depending on the position of the
particle in the plasma or the sheath, respectively. Furthermore, charging of the spheres by UV
radiation is investigated and discussed.
References
[1] A.A. Samarian, B.W. James, Plasma Phys. Control. Fusion. 47(2005), B629.
[2] G. Thieme et al., Faraday Discuss. 137(2008), 157-171.
[3] H. R. Maurer et al., Contrib. Plasma Phys. 51(2011), 218-227.
[4] G. Schubert et al., Contrib. Plasma Phys. 52(2012), 827.
[5] P. Hartmann et al., Plasma Sources Sci. Technol. 23(2014), 045008.
[6] J. Schablinski et al., Phys. Plasmas 22(2015), 043703.
[7] J. Carstensen et al., IEEE Trans. Plasma Sci. 41(2013), 764.
[8] A. Douglass et al., J. Plasma Phys. 82(2016), 615820402.
[9] V. Schneider, H. Kersten, Problems of Atomic Science and Technology. 1(2013), 164-167.
[10] L. Couëdel et al., Contrib. Plasma Phys. 49(2009), 235-259.
