6,014 research outputs found
Particle Detection Algorithms for Complex Plasmas
In complex plasmas, the behavior of freely floating micrometer sized
particles is studied. The particles can be directly visualized and recorded by
digital video cameras. To analyze the dynamics of single particles, reliable
algorithms are required to accurately determine their positions to sub-pixel
accuracy from the recorded images. Typically, straightforward algorithms are
used for this task. Here, we combine the algorithms with common techniques for
image processing. We study several algorithms and pre- and post-processing
methods, and we investigate the impact of the choice of threshold parameters,
including an automatic threshold detection. The results quantitatively show
that each algorithm and method has its own advantage, often depending on the
problem at hand. This knowledge is applicable not only to complex plasmas, but
useful for any kind of comparable image-based particle tracking, e.g. in the
field of colloids or granular matter
3D particle tracking velocimetry using dynamic discrete tomography
Particle tracking velocimetry in 3D is becoming an increasingly important
imaging tool in the study of fluid dynamics, combustion as well as plasmas. We
introduce a dynamic discrete tomography algorithm for reconstructing particle
trajectories from projections. The algorithm is efficient for data from two
projection directions and exact in the sense that it finds a solution
consistent with the experimental data. Non-uniqueness of solutions can be
detected and solutions can be tracked individually
Shuttle wave experiments
Wave experiments on shuttle are needed to verify dispersion relations, to study nonlinear and exotic phenomena, to support other plasma experiments, and to test engineering designs. Techniques based on coherent detection and bistatic geometry are described. New instrumentation required to provide modules for a variety of missions and to incorporate advanced signal processing and control techniques is discussed. An experiment for Z to 0 coupling is included
Overview of the JET results in support to ITER
The 2014–2016 JET results are reviewed in the light of their significance for optimising
the ITER research plan for the active and non-active operation. More than 60 h of plasma
operation with ITER first wall materials successfully took place since its installation in
2011. New multi-machine scaling of the type I-ELM divertor energy flux density to ITER
is supported by first principle modelling. ITER relevant disruption experiments and first
principle modelling are reported with a set of three disruption mitigation valves mimicking
the ITER setup. Insights of the L–H power threshold in Deuterium and Hydrogen are given,
stressing the importance of the magnetic configurations and the recent measurements of
fine-scale structures in the edge radial electric. Dimensionless scans of the core and pedestal
confinement provide new information to elucidate the importance of the first wall material on
the fusion performance. H-mode plasmas at ITER triangularity (H = 1 at βN ~ 1.8 and n/nGW
~ 0.6) have been sustained at 2 MA during 5 s. The ITER neutronics codes have been validated
on high performance experiments. Prospects for the coming D–T campaign and 14 MeV
neutron calibration strategy are reviewed.European Commission (EUROfusion 633053
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