Mapping electron dynamics in highly transient EUV photon-induced plasmas: a novel diagnostic approach using multi-mode microwave cavity resonance spectroscopy

Abstract A dust grain immersed in a low-pressure gas discharge obtains a permanent negative surface charge due to the high mobility of electrons compared to that of ions. This charge essentially governs all fundamental processes in dusty and complex plasmas involving dust grains, neutrals, (an)ions and electrons and—consequently—virtually all industrial applications of these types of plasmas are affected and steered by it. In this work, we have measured the surface charge by application of laser-induced electron detachment from nanosized dust grains in concert with microwave cavity resonance spectroscopy and laser light extinction. The main result is that the electron release is governed by photodetachment rather than by thermionic emission, and that recharging of the dust grains occurs on timescales that are well in agreement with the orbital-motion-limited (OML) theory. The total surface charge density residing on the dust grains inside the laser volume follows from the saturation of the photodetachment signal, which was used in combination with dust density values derived from extinction measurements to estimate the mean dust charge. The negative dust charge on the 140 nm (average) diameter dust grains in this work is obtained to be in the range of 273 − 2519 elementary charges, of which the lower bound matches well with analytical predictions using the orbital-motion-limited (OML) theory.

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Microwave cavity resonance spectroscopy of ultracold plasmas

Physical Review A ◽

10.1103/physreva.100.061801 ◽

2019 ◽

Vol 100 (6) ◽

Cited By ~ 2

Author(s):

M. A. W. van Ninhuijs ◽

K. A. Daamen ◽

J. G. H. Franssen ◽

J. Conway ◽

B. Platier ◽

...

Keyword(s):

Cavity Resonance ◽

Microwave Cavity ◽

Resonance Spectroscopy ◽

Ultracold Plasmas

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The Possibility of Measuring Electron Density of Plasma at Atmospheric Pressure by a Microwave Cavity Resonance Spectroscopy

IEEE Transactions on Plasma Science ◽

10.1109/tps.2021.3050110 ◽

2021 ◽

pp. 1-8

Author(s):

Jinming Li ◽

Aleksandr M. Astafiev ◽

Anatoly A. Kudryavtsev ◽

Chengxun Yuan ◽

Zhongxiang Zhou ◽

...

Keyword(s):

Electron Density ◽

Atmospheric Pressure ◽

Cavity Resonance ◽

Microwave Cavity ◽

Resonance Spectroscopy

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Probing Collisional Plasmas with MCRS: Opportunities and Challenges

Applied Sciences ◽

10.3390/app10124331 ◽

2020 ◽

Vol 10 (12) ◽

pp. 4331

Author(s):

Bart Platier ◽

Tim Staps ◽

Peter Koelman ◽

Marc van der Schans ◽

Job Beckers ◽

...

Keyword(s):

Atmospheric Pressure ◽

Diagnostic Method ◽

Low Pressure ◽

Cavity Resonance ◽

Microwave Cavity ◽

Resonance Spectroscopy ◽

Large Collection ◽

Future Studies ◽

Atmospheric Pressure Plasmas ◽

Impact Studies

Since the 1940s, Microwave Cavity Resonance Spectroscopy (MCRS) has been used to investigate a variety of solids, gases, and low-pressure plasmas. Recently, the working terrain of the diagnostic method has been expanded with atmospheric-pressure plasmas. This review discusses the advancements that were required for this transition and implications of studying highly collisional, with respect to the probing frequencies, plasmas. These developments and implications call for a redefinition of the limitations of MCRS, which also impact studies of low-pressure plasmas using the diagnostic method. Moreover, a large collection of recommendations concerning the approach and its potential for future studies is presented.

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