First results from an event synchronized—high repetition Thomson scattering system at Wendelstein 7-X

Damm, H.; Pasch, E.; Dinklage, A.; Baldzuhn, J.; Bozhenkov, S.; Brunner, K. J.; Effenberg, F.; Fuchert, G.; Geiger, J.; Harris, J. H.; Knauer, J.; Kornejew, P.; Kremeyer, T.; Krychowiak, M.; Schilling, J.; Schmitz, O.; Scott, E. R.; Winters, V.

doi:10.1088/1748-0221/14/09/c09037

Cited by 2 publications

(2 citation statements)

References 18 publications

(18 reference statements)

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“…Two observation optics cover a total of presently 42 volumes on the inboard-and outboard side of the plasma by means of 20 polychromators with 5 spectral channels each. An event-synchronized 18 pulse "burst" sequence within an ∼1.5 ms short interval with full laser energy but repetition then reduced to 5 Hz can be realized for fast events such as the density evolution after pellet injection [25]. In preparation of long-pulse operation an automated laser beam position control is presently implemented to cope with geometrical drifts of the necessary long pathways of more than 30 m.…”

Section: Core Profile Diagnosticsmentioning

confidence: 99%

Core Diagnostics for WENDELSTEIN 7-X Steady-State Exploration Until 18 GJ

Hirsch

Bannmann

Beurskens

et al. 2022

Plasma and Fusion Research

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This contribution provides an overview of the core diagnostics as they are required for W7-X steady-state high-density operation with a divertor and profile control. The inferred profiles then address the stellarator optimization. A particular task is the characterization of fast ion slowing down and -losses, which in a classical stellarator reactor could result in unacceptable wall loads and ultimately are deleterious for the heating efficiency. The energy dissipated during operation, 10 MW • 1800 s impacts on the technical diagnostic realization via loads to in-vessel components, quasi steady-state operation requires adequate data acquisition and control systems.

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Section: Core Profile Diagnosticsmentioning

confidence: 99%

Core Diagnostics for WENDELSTEIN 7-X Steady-State Exploration Until 18 GJ

Hirsch

Bannmann

Beurskens

et al. 2022

Plasma and Fusion Research

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“…For a pellet-injected plasma, two of them were pulsed with a short interval of 200 s 20 . For the same purpose, Thomson scattering diagnostic systems with high-repetition-rate lasers have been developed in W7-X with 12 burst pulses on a 5 Hz basis 21 . Profiles of and were obtained with a time interval of 100 s during the injection process of a cryogenic pellet.…”

Section: Introductionmentioning

confidence: 99%

Electron temperature and density measurement by Thomson scattering with a high repetition rate laser of 20 kHz on LHD

Funaba

Yasuhara

Uehara

et al. 2022

Sci Rep

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Thomson scattering measurements with a high-repetition-rate laser have commenced in the Large Helical Device. As an example of the fast phenomena captured by this diagnostic system, measurements at a 20 kHz repetition-rate in hydrogen pellet-injected plasmas are presented. Signal processing methods for this measurement have been developed and electron temperature profiles with almost 70 spatial points were evaluated at time intervals of 50 $$\upmu$$ μ s. After Raman scattering calibration, electron density profiles were derived. Fast changes in the electron temperature and density profiles within 1 ms were observed.

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First results from an event synchronized—high repetition Thomson scattering system at Wendelstein 7-X

Abstract: Contents 1 Introduction 1 2 Increasing the laser repetition rate 2 3 Realization of the event synchronization 4 4 A possible application: cryogenic H 2 pellet injection 6

Cited by 2 publications

References 18 publications

Core Diagnostics for WENDELSTEIN 7-X Steady-State Exploration Until 18 GJ

Core Diagnostics for WENDELSTEIN 7-X Steady-State Exploration Until 18 GJ

Electron temperature and density measurement by Thomson scattering with a high repetition rate laser of 20 kHz on LHD

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