Confocal laser induced fluorescence (LIF) is a novel diagnostic technique that requires only a single optical port. The confocal technique has recently been used to successfully measure ion velocity distribution functions (IVDFs) in argon with comparable spatial localization to conventional, i.e. intersecting, optical configurations at short distances (f = 15 cm). We demonstrate the extension...
We simulate the measurement performance of the ITER Plasma Position Reflectometry low-field side in-vessel system using a synthetic broadband Ordinary Mode Frequency-Modulated Continuous-Wave reflectometer implemented with REFMUL, a 2D Finite-Difference Time-Domain full-wave Maxwell code. These simulations take into account the system’s location within the vessel as well as its plasma access...
K-shell x-ray spectra of Li- to H-like ions have long been used to determine plasma conditions. The ratio of integrated line intensities is used to determine the temperature. At the density of Non-LTE plasmas (ne ~1021) the K-shell spectrum is not very sensitive to density. We propose using the L-shell emission of open L-shell ions (C- to Li-like) as an alternative to determine both...
Conventional silicon detectors are used due to the availability of good quality homogeneous material, high charge carrier transport properties and their radiation hardness. Silicon detectors will be an important tool to understand the plasma physics in future fusion reactors thanks to their excellent spectroscopic and particle diagnostics performances in harsh environments. The international...
COMPASS is a compact-sized tokamak operated at IPP Prague. A heterodyne radiometer is available for electron cyclotron emission (ECE) diagnostics, originally employed for electron Bernstein wave emission (EBE). Recently, extensive runaway electron (RE) experiments motivated enhancements of suprathermal electron diagnostics, which have been so far focused on runaway losses [O. Ficker et al., NF...
Microparticles ranging from sub-microns to millimeter in size are common form of matter in magnetic fusion environment, which are highly mobile due to their small mass. Different forces in addition to gravity can affect their motion both inside and outside the plasmas. Several recent advances open up new diagnostic possibilities to characterize the particle motion and their forces: high-speed...
A new Thomson scattering (TS) system is being constructed on C-2W for obtaining electron temperature and density profiles with high temporal and spatial resolution. Validating the performance of the TS’s custom designed system components is crucial to obtaining reliable Te and ne profiles of C-2W’s plasma. The diagnostic has two systems: one for measuring the central FRC, and one for measuring...
In order to perform x-ray radiography measurements of high-opacity samples on the National Ignition Facility, we have developed a slit-projection x-ray source that is optimized to produce Bremsstrahlung x-ray emission. Unlike x-ray sources that generate characteristic atomic transition (often the 1s2 − 1s2p transition in ionized He-like atoms), but are generally limited to <30 keV x-rays (from...
A new laser blow-off (LBO) diagnostic was recently installed on the DIII-D tokamak to enable cutting-edge studies of both impurity and electron heat transport in reactor-relevant plasma conditions. Utilizing a high energy (up to 1.2 J), pulsed (50 Hz) Nd:YAG laser and fast, piezo-electric steering optics, this new system is capable of introducing multiple, impurity injections into a single...
Sensors that measure small 3D magnetic fields in tokamaks are susceptible to both DC and AC vacuum field pickup that must be compensated out. In this paper, we present a novel sensor compensation algorithm that uses a layered low-pass filtering technique to efficiently remove the vacuum field pickup generated by both axisymmetric and non-axisymmetric coils. Given that a single technique is...
In order to detect the small-amplitude electron temperature fluctuation associated with the anomalous transport, a correlation ECE (CECE) diagnostic has been designed for EAST since 2016. Detailed description of the design and preliminary results of Te fluctuation measurements are presented here. An independent quasi-optical (QO) antenna was designed, which has an improved poloidal resolution...
Recently, the high frequency Thomson scattering diagnostic system has been upgraded on EAST tokamak, with a temporal resolution up to 4kHz by using a newly designed 1064nm Nd:YAG (neodymium - yttrium aluminium garnet) laser. The laser can fire 10 pulses within one burst at a frequency of 0.5Hz. Each pulse has ~3J power, with a deviation of less than 10%. By using a single laser instead of...
The infrared (IR) part of the DIII-D IR/visible periscope viewing system has been modified for choice of magnification of 1X or 3X (for improved spatial resolution of selected areas such as the upper divertor). No modifications were made to in-vacuum or visible components. The 3X field of view is set by re-aiming one mirror. This allows any part of the 1X view to be examined at 3X...
For the purpose of time-resolved triton burnup measurements in the KSTAR deuterium plasmas, an NE213 liquid scintillation detector has been installed and operated during the 2017 KSTAR campaign. The detector is composed of a 2-inch diameter NE213 scintillator and a photomultiplier tube (PMT). The PMT pulse signal is processed by the data acquisition system of which the field programmable gate...
Inertial Confined Fusion (ICF) is undergoing more detailed research to increase neutron yield, and will require high resolution pictures taken at short distances close to the target. Radiation hard diagnostic instruments are needed. For a future 1E18 neutron yield shot, a camera placed at 10 cm away from the target will be subject to 1E15 neutrons/cm2 fluence, which can damage Si devices. We...
High-temperature, atmospheric pressure plasma systems operated in molecular gases present complex diagnostic challenges. Infrared spectroscopy has been used to make measurements of the absorbance spectrum of complex molecular gas mixtures, and thereby calculate the concentrations and species temperatures in these systems. For high-pressure systems, high spatial gradients arise and high...
The Aerogel Cherenkov Detector for Cygnus (ACD/C) is a time-dependent, x-ray spectral detector that uses SiO2 aerogels spanning an index of refraction (n = 1.02 – 1.07) corresponding to a 1.1 – 2.3 MeV x-ray energy threshold appropriate for pulsed power x-ray sources like Cygnus and Mercury. Aerogels sit between the capability of gas (> 3 MeV) and solids such as glass (0.3 MeV). The detector...
High-temperature, atmospheric-pressure plasma systems operated in molecular gases present complex diagnostic challenges. Schlieren imaging is a technique that can be used to quantitatively measure the density of a gas stream through interpretation of directly-measured deflections from a collimated light source. The presence of hydrodynamic shocks presents a unique challenge to the accuracy...
We present a method for direct measurement of DC conductivity of warm dense matter using single-shot terahertz time-domain spectroscopy (SS-THz-TDS). SS-THz-TDS is a promising tool for characterizing properties of materials undergoing irreversible changes (e.g. the complex refractive index or conductivity). Furthermore, as the period of THz pulses is slow compared to the expected...
The D3He backlighter platform, based on laser-driven implosions of D3He-filled capsules, generates mono-energetic 14.7-MeV and 3.0-MeV protons and has been used with success on OMEGA and the NIF for both radiography and stopping-power studies. We now propose a tri-particle mono-energetic backlighter based on a DT3He gas-filled capsule implosion that will provide 14.7-MeV and 3.0-MeV protons...
Since the beginning of National Ignition Campaign, Gamma Reaction History (GRH) detector at the National Ignition Facility has been providing a fusion bang time, a burn width, as well as the areal density of the compressed carbon-based ablator. The emission of 12C(n, n’) gamma rays from the carbon-based ablator is proportional to the ablator areal density. The gamma-ray based areal density...
A new type of in-vessel Penning gauge, the Wisconsin In-Situ Penning (WISP) gauge, has been developed and successfully implemented in the Wendelstein 7-X island divertor baffle and vacuum vessel. The capacity of the quantitative measurements of the neutral household for light impurities, in particular helium, is important for tokamaks as well as stellarator divertors in order to avoid fuel...
Measurement of DD fusion neutrons is a key diagnostic for magnetized target fusion (MTF) experiments being conducted at General Fusion. When combined with other available diagnostics, the detection of DD fusion neutrons can provide strong constraints on a model of plasma evolution during compression, in particular ion temperature and density. General Fusion plasma compression experiments have...
External plasma heating and current drive systems are vital for magnetically confined fusion devices. These systems rely on exciting wave electric fields (10’s MHz to 100’s GHz) near the scrape off layer by use of an antenna or waveguide structure. Ion Cyclotron (IC), Lower Hybrid (LH), and Electron Cyclotron (EC) range of frequency waves have been quite successfully in fulfilling their...
Matter in the warm, dense regime (T~1-100 eV; ρ~0.01-10 g/cc) is often challenging to diagnose on the timescales of its evolution. For example, matter isochorically heated by a sub-picosecond laser or laser-driven proton beam can rise in temperature by 100 eV over a timescale of ps to 10s of ps, motivating development of sub-ps time-resolved measurement techniques. Here we describe a...
We have begun using a new generation of compact and high-speed hybrid-CMOS digital framing cameras to make time-resolved measurements of the laser heating phase of Magnetized Liner Inertial Fusion (MagLIF) experiments. In the MagLIF target concept, a preheated, magnetized, deuterium-filled Be cylinder is compressed using magnetic direct drive from high-current pulsed power devices such as...
The lithium vapor box divertor is a concept for handling the extreme divertor heat fluxes in magnetic fusion devices. In a baffled slot divertor, plasma interacts with a dense cloud of Li vapor which radiates and cools the plasma, leading to recombination and detachment. Before testing on a tokamak the concept should be validated: we plan to study detachment and heat redistribution by a Li...
Studying the optical conductivity of strongly coupled plasma as function of density is important to understand and model warm dense matter [1]. In high-intensity ultrafast laser excited solids, self-similar plasma expansion occurs in picosecond time scale after the sample is molten, resulting in steepened density gradients [2]. Here we report a new method combining single-shot frequency domain...
We are developing an experimental platform at the NIF to measure x-ray Thomson scattering (XRTS) spectra from indirectly-driven capsule implosions [1]. Recent efforts focus on measuring XRTS at scattering angles as small as 30 degrees, where the spectra become sensitive to collective excitations (plasmons). Such measurements provide improved sensitivity to temperature, and also show promise...
Since 2010, an in-vessel calibration light source (ICLS) has been used periodically on JET to calibrate a range of diagnostics at UV, visible and IR wavelengths. During shutdowns, the ICLS (essentially an integrating sphere) is positioned within the vacuum vessel by the remote handling (RH) system. Following the 2013 run, several changes were made to improve the efficiency and quality of...
A new gas puff(GP) and supersonic molecular beam(SMB) imaging diagnostic system has been developed on HL-2A tokamak to study plasma turbulence and transport dynamics of supersonic molecular beam injection(SMBI) fueling at the edge and scrape-off layer(SOL) of HL-2A tokamak. A specially designed telescope and a high-speed camera are used to observe and record the emission from the neutral gas...
As the H-mode plasma can be maintained for a long time in KSTAR, the inner wall temperature is increased by the heat flux from the plasma. The increased temperature causes damage to the inner wall. The input power of the heat flux and the heating device concentrates in one place, and the local temperature rise may occur, which is a very dangerous factor for maintaining the plasma stably....
A 20cm normal incidence vacuum ultraviolet (VUV) monochromator with fast time response has been developed for measuring edge impurity line emissions in the wavelength range of 300-2000Å on HL-2A tokamak. A 1200 grooves/mm concave holographic grating is adopted to the monochromator with wavelength dispersion of 4nm/mm. The effective aperture of the monochromator is f/4.5. A CEM is used as a...
In the ITER Core Plasma Thomson Scattering the scattered light collection optics system is installed both inside and outside the diagnostic port under vacuum. The length of the optical path (~6 m) and the need to shield the neutron and γ radiation increased the complexity of the system with the inclusion of multiple dog-legs, forcing the use of many elements with optical power.
Multiple rounds...
Charge-exchange spectroscopy on JET has become particularly challenging with the introduction of the ITER-like wall. The impurity spectra are weaker and contaminated by many tungsten lines. We have therefore upgraded the instrumentation to allow the simultaneous measurement of impurity and fuel-ion charge exchange by splitting the light between two pairs of imaging spectrometers using dichroic...
1D 5-μm FWHM spatially resolved high resolution x-ray spectroscopy is needed to diagnose HEDP plasmas with large temperature and density gradients. Magnification is required to overcome the 50-100 μm detector resolution. Experiments with spherical crystals in a sagittally focusing geometry demonstrated ~12 μm resolution. New experiments will attempt to achieve the theoretical limit. To avoid...
CTS diagnostic is a strong tool to measure the ion temperature, fast ion distribution function, and fueling ratio. We have already developed the 77 GHz CTS system, and reported that the obtained CTS spectra responded reasonably according to the ion temperature. The CTS spectrum originated from fast ion is also compared with the simulation result. The result explained the anisotropy of CTS...
The X-ray imaging crystal spectroscopy system installation has been completed for WEST operation. The system aims at providing spatially resolved and high accuracy measurements of ion and electron temperatures, toroidal and poloidal rotation velocities, as well as impurity densities. It consists of three viewing lines hence three spectrometers imaging the full plasma height. Line emission from...
For the use of impurity transport studies a new laser blow-off system was designed and installed on the Wendelstein 7-X (W7-X) stellarator. Basically, the system is able to inject impurity tracer ions in a controlled manner with a repetition frequency of 20 Hz. In particular, a Nd:YAG laser (1 J, 1064 nm) hits a glass plate inside the torus from behind which is coated on the plasma facing...
Gamma ray spectroscopy with high energy and time resolutions is developed on EAST tokamak to study fast ion and runaway electron behaviours. The energy resolution of the spectroscopy is about 3.9% @ 662 keV based on the LaBr3(Ce) scintillator crystal, and the spectroscopy can operate stably at counting rate as high as 2 MHz, monitored by the monitoring system based on two independent light...
In order to improve both the density and particularly the temporal resolution beyond previous dispersion interferometers (DI), a heterodyne technique based on an acousto-optic (AO) cell has been added to the DI. A 40 MHz drive frequency for the AO cell allows density fluctuation measurements into the MHz range. A CO2 laser based heterodyne DI (HDI) was installed on DIII-D. The total beam path...
A plasma-density diagnostic consisting of a Wollaston interferometer is presented for use in the measurement of plasma plumes created in experiments on the OMEGA EP laser. The diagnostic is installed as an additional arm on the 4-omega probe system, a suite of diagnostics that share a 10-ps pulse of 263-nm laser light captured by an imaging system of cone angle f/4. In order to form fringes,...
A Motional Stark Effect (MSE) diagnosis system was developed to measure the plasma current density distribution in the KSTAR tokamak. Currently, the MSE diagnostic system performs data analysis by applying Fourier transform algorithm by using the IDL (Interactive Data Language) software after measurement and digital archiving. However, in order to realize advanced plasma control aiming at the...
Charge-coupled device (CCD) is widely used as a detector of vacuum spectrometers in fusion devices. Recently, deuterium plasma experiments have been started in Large Helical Device (LHD). A lot of neutrons are produced during the D-D operation with energies of 2.45 MeV and 14.1 MeV in D-D and D-T reactions, respectively. Meanwhile, gamma rays are also radiated from plasma facing components...
Gaussian process tomography (GPT) is a recently developed tomography method within the Bayesian probability framework, applied earlier to soft X-ray (SXR) spectroscopy in the W7-AS. By modeling the SXR emissivity field in a poloidal cross-section as a Gaussian process (GP), the reconstruction can be carried out in a robust and extremely fast way. Owing to the short execution time of the...
A tangential soft x-ray crystal spectrometer (XCS) has been designed for ADITYA-U Tokamak to measure plasma toroidal rotation velocity using Doppler shift of the spectral line radiation emitted from the plasma. The electron temperature can also be derived from the intensity ratio of a dielectronic satellite line to the resonance line. For this purpose, X-ray spectral line at 3.945 Å from...
Stable confinement of high-beta (local electron beta ~ 1) is demonstrated with high-energy electrons (T_e > 10 keV) by an X-ray measurement in the RT-1 magnetospheric plasmas. A new Nd:YAG laser Thomson scattering (TS) system has been developed to investigate the mechanism of the high-beta plasma formation in the RT-1. The designed parameters for the TS system is 10 eV < T_e < 50 keV and n_e >...
Phase contrast imaging (PCI) has been recently developed on HL-2A tokamak. In this article we will present the construction and calibration of this diagnostic. The system is able to diagnose the chord integral density fluctuations by measuring the phase shift of a CO2 laser beam with a wavelength of 10.6 um when passing through the plasma region vertically. There are 32 channels of HgCdTe...
Terahertz solid state soures have been successfully applied on an one chord interferometer system on Keda Torus eXperiemnt (KTX), a reversed field pinch machine. For exploring the capacity of microwave source for electro density profile diagnosis of magnetic confinement plasma. The one chord interferometer system has been upgraded to a multi-channel system using the same solid state sources....
A suite of diagnostics was developed to measure particle and heat fluxes arriving at the divertor electrodes of the C-2W experiment at TAE Technologies. The divertor electrodes consist of 4 concentric rings, each equipped with a bolometer, electrostatic energy analyzer, and thermocouple mounted at two opposing azimuthal locations. These probes provide two independent measurements of the power...
We present our recent work on LIBS for surface analysis to better understand complicated plasma-material interactions. We have invented a novel technique, spatially-offset double-pulse (SODP) LIBS, for thin film measurements [1]. In this technique, two laser spots on a material surface are spatially offset by a few mm, while there is no spatial gap for the standard collinear DP-LIBS. Compared...
The ns-Gated Laser Entrance Hole (G-LEH) diagnostic take time-resolved gated images along a single line-of-sight by incorporating a high-speed multi-frame CMOS x-ray imager developed by Sandia National Laboratories into the existing Static X-ray Imager diagnostic at NIF. It was expected to capture two laser-entrance-hole images per shot on its 1024x448 pixel photo-detector array, with...
The X-ray imaging crystal spectrometer (XICS) for the Korea Superconducting Tokamak Advanced Research (KSTAR) device has been actively applying to investigate core toroidal rotation and ion temperature characteristics from helium-like argon spectra since 2009. The XICS system is an important diagnostic for intrinsic toroidal rotation studies for KSTAR because it does not need any external...
The in-vessel neutron flux monitor equipped with Microfission Chambers (MFCs) are exposed to the extreme ITER environment, such as high radiation and high electromagnetic (EM) forces. Therefore, the in-vessel components need to withstand such ITER environment. In this study, various analyses and tests have been carried out for the in-vessel components to show that they can be applied for ITER....
