Diagnostic First Mirrors for Burning Plasma Experiments

Voitsenya, V.S.; Bardamid, A. F.; Belyaeva, A. I.; Bondarenko, V. N.; Costley, A. E.; Галуза, А. А.; Gorshkov, A. V.; Kishimoto, Naoki; Konovalov, V. G.; Orlinskij, D.V.; Rogov, A. V.; Ryzhkov, I. V.; Shapoval, A. H.; Solodovchenko, S. I.; Shtan, A. F.; Vukolov, K.Yu.; Zvonkov, S.N.

doi:10.1007/978-1-4419-8696-2_52

Cited by 11 publications

(18 citation statements)

References 19 publications

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“…In [1] it has been shown that this plasma does effectively remove carbon films deposited on metallic surfaces.…”

Section: Cleaning Mirrors #1 and #5mentioning

confidence: 98%

“…(a) without holder biasing (as in [1]), that is when during the first 130 min for sample #1 and during the first 140 min for sample #5 the ion energy was only defined by the sheath potential (e.g. it did not exceed about 15 eV), and thus chemical erosion was the main mechanism that removed the carbon-based film; (b) with holder biasing to −300 V, that is when starting from the 130th minute for sample #1 and from the 140th minute for sample #5 the deuterium ion energy appreciably exceeded the threshold of physical sputtering for carbon and any other contaminating material.…”

Section: Cleaning Mirrors #1 and #5mentioning

confidence: 99%

“…Until recently, the data necessary to predict the behaviour of mirrors under reactor relevant conditions were only obtained in the simulation experiments [1] performed for mirrors fabricated of different metals with different structures (i.e. a polycrystal, a single crystal or a metal film on a metal substrate).…”

Section: Introductionmentioning

confidence: 99%

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Effect of exposure inside the Large Helical Device vessel on the optical properties of stainless steel mirrors

Voitsenya

Sagara

Belyaeva

et al. 2005

Plasma Devices and Operations

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During the third experimental campaign, three stainless steel mirrors were exposed inside the Large Helical Device (LHD) vacuum vessel and, in order to measure the change in their spectral reflectance R(λ), the effect of this exposure was measured at normal incidence (λ = 200-700 nm). The mirrors located in the divertor region and in the diagnostic port became coated with carbon-based films; however, the mirror placed closest to the plasma confinement volume became cleaner than it had initially been. The characteristics of the films were obtained by different techniques. The deposited films were slowly removed by repeatedly exposing the mirrors to low-energy ions of deuterium plasma, and R(λ) was measured after every exposure. In the present paper we compare the reflectance behaviour during this cleaning procedure and the reflectance calculated in the framework of a model assuming that a half-transparent film is formed on stainless steel substrate. The n(λ) and k(λ) data for carbon-based films were taken from experiments and the literature.

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“…In [1] it has been shown that this plasma does effectively remove carbon films deposited on metallic surfaces.…”

Section: Cleaning Mirrors #1 and #5mentioning

confidence: 98%

Section: Cleaning Mirrors #1 and #5mentioning

confidence: 99%

See 1 more Smart Citation

Effect of exposure inside the Large Helical Device vessel on the optical properties of stainless steel mirrors

Voitsenya

Sagara

Belyaeva

et al. 2005

Plasma Devices and Operations

Self Cite

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“…These mirrors allow the use of labyrinths to preserve the shielding capability even though the penetration size is larger than would have been necessary for a fiber-optic based configuration. However there are serious questions of maintaining reflectivity and polarization information through the mirror train, especially as the front-end mirror may see coating or erosion caused by the nearby plasma [58]. This last issue is one of major concern to the designers of ITER diagnostics who have encouraged many test-programs on operating devices (chapter 12).…”

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confidence: 99%

Plasma Measurements: An Overview of Requirements and Status

Young¹

2008

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This paper introduces this special issue on plasma diagnostics for magnetic fusion devices. Its primary purpose is to relate the measurements of plasma parameters to the physics challenges to be faced on operating and planned devices, and also to identify the diagnostic techniques that are used to make these measurements. The specific physics involved in the application of the techniques will be addressed in subsequent chapters.This chapter is biased toward measurements for tokamaks because of their proximity to the burning plasma frontier, and to set the scene for the development work associated with ITER. Hence, there is some emphasis on measurements for alpha-physics studies and the needs for plasma measurements as input to actuators to control the plasma, both for optimizing the device performance and for protection of the surrounding material.The very different approach to the engineering of diagnostics for a burning plasma is considered, emphasizing the needs for new calibration ideas, reliability and hardness against, and compatibility with, radiation. New ideas take a long time to be converted into "work-horse" sophisticated diagnostics so that investment in new developments is essential for ITER, particularly for the measurement of alpha-particles

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“…Another complication arises with this type of arrangement in that good reflecting surfaces will have to be placed close to the plasma. Sputtering of the reflecting surface by neutral particles from the plasma has been shown to be a concern and it is being investigated for ITER [11].…”

Section: Radiation Impact On Diagnosticsmentioning

confidence: 99%

Challenges for plasma diagnostics in a next step device (FIRE)

Young¹

Proceedings of the 19th IEEE/IPSS Symposium on Fusion Engineering. 19th SOFE (Cat. No.02CH37231)

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Abstract--The physics program of any next step tokamak such as FIRE sets demands for plasma measurement which are at least as comprehensive as on present tokamaks, with the additional capabilities needed for control of the plasma and for understanding the effects of the alpha-particles. The diagnostic instrumentation must be able to provide the fine spatial and temporal resolution required for the advanced tokamak plasma scenarios. It must also be able to overcome the effects of neutron-and gamma-induced electrical noise in ceramic components or detectors, and fluorescence and absorption in optical components. There are practical engineering issues of minimizing radiation streaming while providing essential diagnostic access to the plasma. Many diagnostics will require components at or close to the first wall, e.g. ceramics and MI cable for magnetic diagnostics and mirrors for optical diagnostics; these components must be mounted to operate, and survive, in fluxes which require special material selection. A better set of diagnostics of alpha-particles than that available for TFTR is essential; it must be qualified well before moving into D-T experiments. A start has been made to assessing the potential implementation of key diagnostics for the FIRE device. The present status is described.

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Diagnostic First Mirrors for Burning Plasma Experiments

Cited by 11 publications

References 19 publications

Effect of exposure inside the Large Helical Device vessel on the optical properties of stainless steel mirrors

Effect of exposure inside the Large Helical Device vessel on the optical properties of stainless steel mirrors

Plasma Measurements: An Overview of Requirements and Status

Challenges for plasma diagnostics in a next step device (FIRE)

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