Study of spoke rotation, merging and splitting in HiPIMS plasma

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216224%3A14310%2F17%3A00094904" target="_blank" >RIV/00216224:14310/17:00094904 - isvavai.cz</a>

Result on the web

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DOI - Digital Object Identifier

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Result language

angličtina

Original language name

Study of spoke rotation, merging and splitting in HiPIMS plasma

Original language description

Study of self-organized structures called spokes was performed in the HiPIMS plasma using simultaneous broadband optical screening via ICCD camera (200 ns time scale) and the embedded probes measuring the local current delivered by the spoke to the target. As a spoke passed over a set of embedded probes in the niobium cathode target, a distinct local current modulation is observed. Typically the current modulation was up to twice the average value, matching well with the radially integrated optical emission intensities obtained by the ICCD. The dual diagnostic system enabled the observation of a set of spokes as they rotated and the events of the spoke merging and splitting were recorded. The two spokes with similar sizes and intensities were observed to merge into one larger spoke, while the retaining the velocity of the trailing spoke. In the merged spoke both the plasma emission intensity and current collected by the embedded probes was redistributed to have their maximum at a trailing edge. The reverse process, in which spokes split was also observed. The total charge collected by the embedded probes during the spoke splitting was conserved. After the spoke merging or splitting events occurred, the new spoke configuration was not always stable in time. Often the large spoke split into two smaller spokes only to reform a short time later. However for a given experimental conditions only a slight variation from the average mode number m was observed (typically a change of m = 1). In addition a simple phenomenological model was developed to relate the spoke mode number m with the spoke dimensions, spoke velocity and gas atom velocity.

Czech name

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Czech description

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Type

O - Miscellaneous

CEP classification

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OECD FORD branch

10305 - Fluids and plasma physics (including surface physics)

Project

Result was created during the realization of more than one project. More information in the Projects tab.

Continuities

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Publication year

2017

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů