<i>In-situ</i> analysis of optically thick nanoparticle clouds

Kirchschlager, Florian; Wolf, S.; Greiner, Franko; Groth, Sebastian; Labdon, Aaron

doi:10.1063/1.4982645

Cited by 14 publications

(21 citation statements)

References 24 publications

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“…Under these conditions radiative transfer simulations should be applied. In such Monte Carlo simulations [15] a large number of photons are followed on their way through the nanodusty plasma experiencing multiple scattering events until eventually reaching the detector. Figure 5(a) shows the multiply scattered light from a thin horizontal laser beam, entering the dust cloud from the left and reaching the x-y detector plane.…”

Section: Nanoparticle Size -Mie-ellipsometrymentioning

confidence: 99%

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Diagnostics and characterization of nanodust and nanodusty plasmas

et al. 2018

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Plasmas growing or containing nanometric dust particles are widely used and proposed in plasma technological applications for production of nano-crystals and surface deposition. Here, we give a compact review of in-situ methods for the diagnostics of nanodust and nanodusty plasmas, which have been developed in the framework of the SFB-TR24 to fully characterize these systems. The methods include kinetic Mie ellipsometry, angular-resolved Mie scattering, and 2D imaging Mie ellipsometry to get information about particle growth processes, particle sizes and particle size distributions. There, also the role of multiple scattering events is analyzed using radiative transfer simulations. Computed tomography and Abel inversion techniques to get the 3D dust density profiles of the particle cloud will be presented. Diagnostics of the dust dynamics yields fundamental dust and plasma properties like particle charges and electron and ion densities. Since nanodusty plasmas usually form dense dust clouds electron depletion (Havnes effect) is found to be significant.

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Section: Nanoparticle Size -Mie-ellipsometrymentioning

confidence: 99%

“…The circles show an experimental curve, the simulated curve set can be used to estimate the particle density and the particle radius for optically thick particle clouds. From [15]. ent particle densities (lines).…”

Section: Nanoparticle Size -Mie-ellipsometrymentioning

confidence: 99%

Diagnostics and characterization of nanodust and nanodusty plasmas

et al. 2018

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“…The code solves the equation of radiative transfer numerically applying the Monte-Carlo method. POLARIS was initially designed to simulate the observational appearance of astronomical § While the pioneering study (Kirchschlager et al 2017) was performed with Mol3D (Ober et al 2015), for this study we use the more versatile radiative transfer software POLARIS because of its better flexibility in terms of already implemented radiation sources and possible model geometries. Comparing the results in Kirchschlager et al (2017) with results of corresponding POLARIS simulations, we find no significant deviations.…”

Section: The Radiative Transfer Code Polaris §mentioning

confidence: 99%

Radiative transfer simulations for in-situ particle size diagnostic in reactive, particle growing plasmas

Kobus

Petersen²,

Greiner³

et al. 2022

J. Phys. D: Appl. Phys.

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When considering particles produced in reactive plasmas, their basic properties, such as refractive index and grain size often need to be known. They can be constrained both ex-situ, e.g., by microscopy, and in-situ by polarimetry, i.e., analyzing the polarization state of scattered light. Polarimetry has the advantage of temporal resolution and real-time measurement, but the analysis is often limited by the assumption of single scattering and thus optically thin dust clouds. This limits the investigation of the growth process typically to grain sizes smaller than about 200 nm. Using 3D polarized radiative transfer simulations, however, it is possible to consider multiple scattering and to analyze the properties of dense particle clouds. We study the impact of various properties of dust clouds on the scattering polarization, namely the optical depth of the cloud, the spatial density distribution of the particles, their refractive index as well as the particle size dispersion. We find that ambiguities can occur regarding optical depth and spatial density distribution as well as regarding refractive index and particle size dispersion. Determining the refractive index correctly is especially important as it has a strong impact on the derived particle sizes. With this knowledge, we are able to design an in-situ diagnostics strategy for the investigation of the particle growth process based on radiative transfer simulations which are used to model the polarization over the whole growth process. The application of this strategy allows us for the first time to analyze the polarization measured during a growth experiment in a reactive argon-acetylene plasma for particle radii up to 280 nm.

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“…Diagnostics of the dust component of dusty plasmas has the goal to measure several quantities: size and chemical composition, [105,112,[165][166][167][168][169] positions and velocities of single microparticles, [170][171][172] their number density, and charge. [21,[173][174][175][176][177] Diagnostics of size and chemical composition makes sense only in case they are not known with sufficient accuracy or significantly change during the experiment, that is, when the dust particles are grown in the plasma or undergo significant sputtering.…”

Section: Diagnostics Of Dustmentioning

confidence: 99%

Physical aspects of dust–plasma interactions

Pustylnik

Pikalev

Zobnin

et al. 2021

Contributions to Plasma Physics

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Low‐pressure gas discharge plasmas are known to be strongly affected by the presence of small dust particles. This issue plays a role in the investigations of dust particle‐forming plasmas, where the dust‐induced instabilities may affect the properties of synthesized dust particles. Also, gas discharges with large amounts of microparticles are used in microgravity experiments, where strongly coupled subsystems of charged microparticles represent particle‐resolved models of liquids and solids. In this field, deep understanding of dust–plasma interactions is required to construct the discharge configurations which would be able to model the desired generic condensed matter physics as well as, in the interpretation of experiments, to distinguish the plasma phenomena from the generic condensed matter physics phenomena. In this review, we address only physical aspects of dust–plasma interactions, that is, we always imply constant chemical composition of the plasma as well as constant size of the dust particles. We also restrict the review to two discharge types: dc discharge and capacitively coupled rf discharge. We describe the experimental methods used in the investigations of dust–plasma interactions and show the approaches to numerical modelling of the gas discharge plasmas with large amounts of dust. Starting from the basic physical principles governing the dust–plasma interactions, we discuss the state‐of‐the‐art understanding of such complicated, discharge‐type‐specific phenomena as dust‐induced stratification and transverse instability in a dc discharge or void formation and heartbeat instability in an rf discharge.

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In-situ analysis of optically thick nanoparticle clouds

Cited by 14 publications

References 24 publications

Diagnostics and characterization of nanodust and nanodusty plasmas

Diagnostics and characterization of nanodust and nanodusty plasmas

Radiative transfer simulations for in-situ particle size diagnostic in reactive, particle growing plasmas

Physical aspects of dust–plasma interactions

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