The first fast ion experiments in Wendelstein 7-X were performed in 2018. They are one of the first steps in demonstrating the optimised fast ion confinement of the stellarator. The fast ions were produced with a neutral beam injection (NBI) system and detected with infrared cameras (IR), a fast ion loss detector (FILD), fast ion charge exchange spectroscopy (FIDA), and post-mortem analysis of plasma facing components. The fast ion distribution function in the plasma and at the wall is being modelled with the ASCOT suite of codes. They calculate the ionisation of the injected neutrals and the consecutive slowing down process of the fast ions. The primary output of the code is the multidimensional fast ion distribution function within the plasma and the distribution of particle hit locations and velocities on the wall. Synthetic measurements based on ASCOT output are compared to experimental results to assess the validity of the modelling. This contribution presents an overview of the various fast ion measurements in 2018 and the current modelling status. The validation and data-analysis is on-going, but the wall load IR modelling already yield results that match with the experiments.

Wendelstein 7-X

Neutral Beam Injection

10.1088/1748-0221/14/10/c10012

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Citations (17)

FUEGO — Fire Urgency Estimator in Geosynchronous Orbit — A Proposed Early-Warning Fire Detection System

Remote Sensing (2013)

C. R. Pennypacker M. Jakubowski Maggi Kelly M. Lampton Christopher C. Schmidt

Current and planned wildfire detection systems are impressive but lack both sensitivity and rapid response times. A small telescope with modern detectors and significant computing capacity in geosynchronous orbit can detect small (12 m2) fires on the surface of the earth, cover most of the western United States (under conditions of moderately clear skies) every few minutes or so, and attain very good signal-to-noise ratio against Poisson fluctuations in a second. Hence, these favorable statistical significances have initiated a study of how such a satellite could operate and reject the large number of expected systematic false alarms from a number of sources. Here we present both studies of the backgrounds in Geostationary Operational Environmental Satellites (GOES) 15 data and studies that probe the sensitivity of a fire detection satellite in geosynchronous orbit. We suggest a number of algorithms that can help reduce false alarms, and show efficacy on a few. Early detection and response would be of true value in the United States and other nations, as wildland fires continue to severely stress resource managers, policy makers, and the public, particularly in the western US. Here, we propose the framework for a geosynchronous satellite with modern imaging detectors, software, and algorithms able to detect heat from early and small fires, and yield minute-scale detection times.

Fire Detection

10.3390/rs5105173

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Citations (16)

Determination of diethyllead in the urine by flameless atomic absorption spectrometry.

Occupational and Environmental Medicine (1985)

Z Turlakiewicz M. Jakubowski Jadwiga Chmielnicka

A method for the determination of diethyllead in urine by flameless atomic absorption spectrometry after chelation with glyoxal-bis (2-hydroxyanil) and extraction of the formed complex with methyl isobutyl ketone is described. The method is specific in relation to both triethyllead and inorganic lead. The limit of detection was 3.2 micrograms Pb/l and the relative standard deviation in the concentration range 20-100 micrograms Pb/l was 0.076.

Methyl isobutyl ketone

Relative standard deviation

Glyoxal

10.1136/oem.42.1.63

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Citations (7)

Neutral particle fluxes on the divertor during overload mimic scenarios in Wendelstein 7-X

Alexandra LeViness P. Drewelow J. Lore G. Schlisio G. A. Wurden

Wendelstein 7-X

Particle (ecology)

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The Optimization of the Ergodic Structure of the Dynamic Ergodic Divertor In The TEXTOR Tokamak

AIP conference proceedings (2006)

M. Jakubowski

The dynamic ergodic divertor (DED) in TEXTOR is designed to provide a perturbed volume in the plasma edge in order to control heat and particle exhaust. The stochastic boundary layer is generated in the outermost region of the plasma, which can be divided into ergodic and laminar regions. The topology of the magnetic field is substantial for the transport properties and plasma parameters. It is expected that the formation of the proper laminar zone allows decoupling the plasma edge from the core. Due to enhancement of the radial electron heat transport in the ergodic region the electron temperature in the plasma boundary is reduced. Therefore one needs to find the proper ratio of the ergodic and laminar zone, which gives optimal performance of the divertor. The structure of the perturbed volume strongly depends on the safety factor profile and the plasma pressure. At the higher level of ergodization (i.e. at higher plasma current and lower beta poloidal) the laminar zone is dominant, while at the lower level of ergodization the ergodic region is more important. The topology of the perturbed volume is modeled with the ATLAS‐code and basing on the results of modeling the experiments are performed and compared to the calculated structures.

Ergodicity

10.1063/1.2168821

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Citations (2)

Magnetic field topology and heat flux patterns under the influence of the dynamic ergodic divertor of the TEXTOR tokamak

M. Jakubowski

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Citations (0)

Modeling and Experimental Validation of Physics Enabled by W7-X Scraper Element Divertor Components

J. Lore J. H. Harris Arnold Lumsdaine F. Effenberg H. Frerichs

Scraper site

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Control of Type-I ELMs by Resonant Magnetic Perturbations in ITER Similar Shaped Plasmas on DIII-D

M.E. Fenstermacher T.E. Evans R. A. Moyer T.H. Osborne P.B. Snyder

Using the new high triangularity pumping capability on DIII-D, suppression of large Type-I edge localized modes (ELMs) by n=3 resonant magnetic perturbations (RMPs) from an internal coil (I-coil) was extended to ITER similar shape (ISS) plasmas with the ITER pedestal collisionality, e * ~ 0.1. Comparison of a series of ISS plasmas with different n=3 RMPs, n=1 field-error correction, and residual intrinsic field-errors showed that for complete ELM suppression, the region of island overlap in the edge, calculated with vacuum fields, was greater than approximately 3-4 times the width of the total pressure pedestal.

Pedestal

Collisionality

DIII-D

Resonant magnetic perturbations

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Results of ITER Test Blanket Module Mock-Up Experiments on DIII-D

J. Snipes M. J. Schaffer P. Gohil Antti Salmi Diii-D Team

Author(s): Snipes, JA; Schaffer, MJ; Gohil, P; De Vries, P; Fenstermacher, ME; Evans, TE; Gao, X; Garofalo, AM; Gates, DA; Greenfield, CM; Heidbrink, WW; Kramer, GJ; Liu, S; Loarte, A; Nave, MFF; Oyama, N; Park, JK; Ramasubramanian, N; Reimerdes, H; Saibene, G; Salmi, A; Shinohara, K; Spong, DA; Solomon, WM; Tala, T; Boedo, JA; Budny, R; Chuyanov, V; Doyle, EJ; Jakubowski, M; Jhang, H; Nazikian, RM; Pustovitov, VD; Schmitz, O; Osborne, TH; Srinivasan, R; Taylor, TS; Wade, MR; You, KI; Zeng, L

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Wendelstein 7-X Near Real-Time Image Diagnostic System for Plasma-Facing Components Protection

Fusion Science & Technology (2017)

A. Puig Sitjes M. Jakubowski Adnan Ali P. Drewelow V. Moncada

The Wendelstein 7-X (W7-X) fusion experiment is aimed at proving that the stellarator concept is suitable for a future fusion reactor. Therefore, it is designed for steady-state plasmas of up to 30 min, which means that the thermal control of the plasma-facing components (PFCs) is of vital importance to prevent damage to the device.In this paper an overview of the design of the Near Real-Time Image Diagnostic System (hereinafter called "the System") for PFCs protection in W7-X is presented. The goal of the System is to monitor the PFCs with high risk of permanent damage due to local overheating during plasma operations and to send alarms to the interlock system. The monitoring of the PFCs is based on thermographic and video cameras, and their video streams are analyzed by means of graphics processing unit–based computer vision techniques to detect the strike line, hot spots, and other thermal events. The video streams and the detected thermal events are displayed online in the control room in the form of a thermal map and permanently stored in the database. In order to determine the emissivity and maximum temperature allowed, a pixel-based correspondence between the image and the observed device part is required. The three-dimensional geometry of W7-X makes the System particularly sensitive to the spatial calibration of the cameras since hot spots can be expected anywhere, and a full segmentation of the field of view is necessary, in contrast to other regions of interest–based systems. A precise registration of the field of view and a correction of the strong lens distortion caused by the wide-angle optical system are then required.During the next operation phase the uncooled graphite divertor units will allow the System to be tested without risk of damaging the divertors in preparation for when water-cooled high-heat-flux divertors will be used.

Overheating (electricity)

Wendelstein 7-X

Fusion power

10.1080/15361055.2017.1396860

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Citations (28)