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Novel power exhaust solutions are being developed to address the challenge of integrating a high performance fusion core plasma with a well-protected divertor, if the single null configuration does not scale to a reactor device. This work aims to elucidate the physics mechanisms responsible for the reduction in peak target heat flux in configurations with multiple X-points. Experimental studies on tokamak à configuration variable in the Snowflake Minus configuration are extended to a novel configuration with three nearby divertor X-points, termed a Jellyfish, allowing us to enhance the expected effects of an additional divertor X-point. These studies are complemented by simplified 1D scrape-off layer (SOL) modeling with the SPLEND1D code and by interpretative modeling with the edge transport code EMC3-EIRENE applied to the Snowflake Minus, to further elucidate some of the key underlying processes. We find that configurations with multiple nearby X-points, and increased near-SOL connection length, exhibit reductions in peak target heat flux and an earlier detachment onset compared to a reference single null configuration, consistent with expectations from SPLEND1D. A strong correlation is experimentally observed between the radially localized radiated power and connection length. While this does not necessarily map to higher total divertor radiative losses for configurations with multiple X-points, it can, at least, provide some control over the radial position of the spatial radiation distribution. Experiments are shown to exhibit radial striations in the emissivity of multiple spectral lines in the inter-null region in these configurations. Although comparisons with EMC3-EIRENE simulations support enhanced cross field transport in the inter-null region, additional transport physics is required in the model to obtain a quantitative match with experiment. No significant differences in divertor-core compatibility are attributed to the presence of additional divertor X-points. However, impurity source optimization is required in such geometries to ensure a low core impurity content is maintained. [ABSTRACT FROM AUTHOR]

This study employs the established momentum transport analysis at ASDEX Upgrade [Zimmermann et al., Nucl. Fusion 63, 124003 (2023)] to investigate the parametric variations of the momentum transport coefficients in the core of H-mode plasmas. These experimental results are compared to a comprehensive database of gyrokinetic calculations. Generally, good agreement between predicted and measured diffusive and convective transport coefficients is found. The predicted and measured Prandtl numbers correlate most dominantly with the magnetically trapped particle fraction. The experimentally inferred pinch numbers strongly depend on the logarithmic density gradient and magnetic shear, consistent with the theoretical predictions of the Coriolis pinch. The intrinsic torque from residual stress in the inner core is small, scales with the local logarithmic density gradient, and the data indicate a possible sign reversal. In the outer periphery of the core, the intrinsic torque is always co-current-directed and scales with the pressure gradient. This is consistent with prior experimental findings and global, non-linear gyrokinetic predictions. It suggests that profile shearing effects generate the intrinsic torque in the inner core. Toward the outer core, most likely, effects from E × B -shearing become more influential. These results offer the first comprehensive picture of this transport channel in the core plasma and contribute to validating the corresponding theoretical understanding. The derived scaling laws are used to construct a reduced momentum transport model, which has been validated against an additional dataset. This demonstrates that the model captures the essential contributions to momentum transport in the core of H-mode plasmas. [ABSTRACT FROM AUTHOR]

The Tokamak à Configuration variable (TCV) is equipped with two neutral beam injection (NBI) systems delivering up to 1.2 MW each for pulse durations of up to 2 s. The first system (NBI1), designed for an injection energy in the range of 25 to 30 keV has been operational since 2016. The existing concrete neutron shielding of the experimental hall proved insufficient for fully protecting human accessible areas, limiting the number of daily plasma pulses using NBI1. The recently commissioned second system (NBI2) is designed for injection synergies in the range 50 to 60 keV. Both systems are tangentially oriented in opposite directions in order to permit experiments with low or no net torque. Calculations with the TRANSP and ORBIS heating codes show that neutron rates from deuterium-deuterium fusion reactions may be as high as 1014 n/s, up to 10 times higher than with the lower energy beam only. This is due both to the ~five times larger beam-plasma neutron rates from the higher energy beam and to an exceptionally high contribution from beam-beam reactions between the opposing beams. The radiation protection policy at the Swiss Plasma Center is that all staff members be considered as members of the general public, limiting the daily personal dose to 4 µSv. This is also the maximum admissible daily dose in any publicly accessible zone, whether occupied or not. Currently, with only the lower energy beam, this limit can be attained in the control room adjacent to the device hall after only five NBI pulses out of a possible 30 daily pulses. To allow for exploitation of the two beams at full specifications, the source side of the existing barite concrete walls of the 15 × 20 × 8 m large TCV hall will be covered with 20-cm-thick polythene (PE) cladding and a ceiling made of 35-cm-thick PE will be added. The total mass of PE will be 200 tons. The usage of PE at this scale for neutron shielding is unprecedented at any fusion research facility. [ABSTRACT FROM AUTHOR]

Introduction: The primary objective of this study was to compare the radiological and clinical results of anterograde and retrograde screwing in subtalar arthrodesis using a single compression screw. The secondary objective was to evaluate the subjective results and consolidation of this procedure. The hypotheses were that isolated screw fixation was sufficient to achieve good consolidation and that there was no difference between the two techniques with a similar rate of bone fusion. Methods: This is a monocentric, retrospective, radio-clinical study based on 99 patients (101 feet), 58 males and 41 females, with an average age of 64 years. The main aetiology was post-traumatic osteoarthritis, which represented 51% of cases. Two groups were formed: group A (52 feet) consisting of fixed arthrodesis with ascending (retrograde) screwing and group D (49 feet) consisting of fixed arthrodesis with descending (anterograde) screwing. The two groups were statistically comparable in terms of demographic data as well as aetiologies and comorbidities. Arthrodeses which were not fused at 6 months were reassessed at one year and in the event of any radio-clinical doubt regarding consolidation, an additional CT scan was prescribed. Average post-operative follow-up was 11 ± 5 years (2–27 years). Results: Ninety-two arthrodeses (93%) were fused at one year and 9 were considered to be in non-union, 5 (9.8%) in group A, and 4 (8.3%) in group D. We recorded 30 complications, 22 of which were due to a conflict with the screw head, 18 (34.5%) in group A and 4 (8.3%) in group D (p = 0.03). Conflict between the screw head and the heel led to the removal of the screw after consolidation of the arthrodesis. The clinical results were evaluated using Odom's criteria. Nine per cent of patients described their results as excellent, 29% as good, 51% as satisfactory and 11% found the result to be poor. Conclusion: The fusion rate for isolated compression screw arthrodesis is good, and there is no difference between anterograde and retrograde screws. However, the discomfort caused by the screw head being insufficiently embedded in the retrograde group led to a non-negligible number of additional surgeries to remove the screw. [ABSTRACT FROM AUTHOR]

High resolution spectroscopy on the Tokamak à Configuration Variable (TCV) divertor plasma provided Doppler broadening measurements to infer the ion and neutral temperature of injected helium gas. This paper presents the Divertor Spectroscopy System's (DSS) access to He II ion temperature measurements over a broad range, ≈0.5–15 eV, with an uncertainty of <10% for most of the studied plasma discharges. TCV's shaping flexibility was employed to validate these measurements against Thomson scattering across the DSS lines of sight. In detachment-related experiments, Ti(He II) ≃ Te, making this diagnostic a reliable thermometer along the divertor leg plasma over the wide range of magnetic equilibria and divertor configurations achievable in TCV. A detailed description of the diagnostic hardware, data analysis, and sources of uncertainty is presented. [ABSTRACT FROM AUTHOR]

We present the design and operation of a suite of Gas Puff Imaging (GPI) diagnostic systems installed on the Tokamak à Configuration Variable (TCV) for the study of turbulence in the plasma edge and Scrape-Off-Layer (SOL). These systems provide the unique ability to simultaneously collect poloidal 2D images of plasma dynamics at the outboard midplane, around the X-point, in both the High-Field Side (HFS) and Low-Field Side (LFS) SOL, and in the divertor region. We describe and characterize an innovative control system for deuterium and helium gas injection, which is becoming the default standard for the other gas injections at TCV. Extensive pre-design studies and the different detection systems are presented, including an array of avalanche photodiodes and a high-speed CMOS camera. First results with spatial and time resolutions of up to ≈ 2 mm and 0.5 µs, respectively, are described, and future upgrades of the GPI diagnostics for TCV are discussed. [ABSTRACT FROM AUTHOR]

Measurements of radiated power are critical for characterizing and optimizing tokamak performance. The RADCAM system, comprising arrays of foil bolometers, Absolute eXtreme UltraViolet (AXUV), and filtered soft x-ray diodes, has been constructed to provide improved measurements of plasma radiation on "Tokamak a Configuration Variable" (TCV). An overview of the physical geometry, electronics, and design of the system is provided. The construction of the bolometer foils together with the improved sensitivity characteristics resulting from the inclusion of an anti-reflection carbon coating are presented. The large number of lines of sight in RADCAM are shown to significantly increase the spatial resolution over the legacy system. The system calibration procedure is detailed, and the mean system sensitivity is shown to vary by less than 5% over 1000 discharges. Additionally, the methodology for cross-calibration of the AXUV diodes with the bolometer foils is presented and applied to generate high temporal resolution measurements. The RADCAM radiation camera system is a compact, versatile system that is demonstrated to provide high resolution profiles of the radiated power in TCV. [ABSTRACT FROM AUTHOR]

Purpose: The aim was to assess the consequences of quadriceps tendon (QT) harvest on knee extensor strength after anterior cruciate ligament reconstruction (ACL-R) compared to hamstring tendon (HT) autograft. Secondary objectives were to evaluate flexor strength recovery and search for correlation between strength status and functional outcome. Methods: This a retrospective cohort of 44 patients who underwent ACL-R using either QT (25) or HT (19). Median age was 31.1 years. We assessed thigh muscle strength thanks to concentric iso kinetic evaluation (peak torque) at 60°.s−1, 180°.s−1, 240°.s−1 and eccentric at 30°.s−1, 7 months on average after surgery. Muscle strength values were compared to the uninjured leg in order to calculate a percentage of deficit as well as unilateral hamstring/quadriceps (H/Q) ratios. KOOS score was obtained at a mean follow-up of 18 months. Results: Extensor strength deficit (concentric 60°.s−1) was one average 33.1% in the QT group and 28.2% in the HT group (p = 0.42). Difference of flexor strength deficit (concentric 60°.s−1) was close to be significant with 5% and 12% of deficit in the QT and HT group, respectively (p = 0.1), and statistically significant for high angular velocity (14% versus 3% at 240°.s−1, p = 0.04). H/Q ratios were comparable in both groups ranging from 0.62 to 0.78. Quadriceps muscle strength deficit was negatively correlated with the KOOS score (Pearson coefficient = −0.4; p = 0.005). Conclusion: QT autograft harvest does not yield significant quadriceps muscle weakness after ACL-R, which appear to be a pejorative factor for functional outcome. Level of evidence: IV, Retrospective study. [ABSTRACT FROM AUTHOR]

Evidence that density shoulder broadening is dependent on high main-chamber neutral density is presented. Shoulder broadening does not occur when the sources for main-chamber neutrals are minimized using divertor baffles and wide gaps to the first wall (∼3× the density decay length). Removing the baffles or reducing the gap to the inner wall both act to increase the density shoulder amplitude in otherwise identical TCV discharges. Radial turbulent transport is correlated with shoulder amplitude. [ABSTRACT FROM AUTHOR]

This work presents a quantitative test of SOLPS-ITER simulations against tokamak à configuration variable (TCV) L-mode experiments. These simulations account for drifts, currents, kinetic neutrals, and carbon impurities providing the most complete edge transport simulations for TCV to date. The comparison is performed on nominally identical discharges carried out to assess the effectiveness of TCV's divertor baffles in the framework of the European Plasma Exhaust program and employs numerous edge diagnostics providing a detailed code-experiment benchmark for TCV. The simulations show a qualitative consistency, but the quantitative differences remain, which are assessed herein. It is found that, for a given separatrix density, the simulations most notably yield a colder, and denser, divertor state with a higher divertor neutral pressure than measured. [ABSTRACT FROM AUTHOR]

Purpose: The aims of this study were (1) to collect prospectively all tibial plateau fractures admitted to our department, over two ski seasons, and to classify them according to the Schatzker and AO classifications; (2) to assess if these classifications are accurate enough to include all types of fractures; and (3) to compare theses fractures with the series found in the literature, which included very few or no skiing accidents. Methods: During the 2016-2017 and 2017-2018 ski seasons, we prospectively included 116 tibial plateau fractures caused by downhill skiing accidents. All patients underwent standard X-rays and 2D and 3D CT scans. The fractures were classified according to the AO and Schatzker revisited classifications. Results: The full series consisted of 56 males (48%) and 60 females (52%), aged 49 ± 16 years (18-77). There were 60 type B (52%) and 56 type C fractures (48%) for AO classification and 45.5% types I, II and III and 54.5% types IV, V and VI for Schatzker classification. Thirty-five frontal fractures (30%) were not differentiated under the AO classification and, likewise, associated tibial spine fractures (28.5%) were not differentiated in the Schatzker classification. We were also unable to classify anterior tibial tuberosity fractures (14.5%) and fibula head fractures (8%). The anatomo-pathological types were not so different from road traffic accidents. Conclusion: Contrary to our hypothesis, the anatomical-pathological damage in tibial plateau fractures resulting from downhill skiing accidents was barely any different from those found in road traffic accidents. However, despite progress in classifications with the emergence of 3D CT scans, it is still not always possible to categorise all fractures within a given classification. [ABSTRACT FROM AUTHOR]

Divertor detachment and alternative divertor magnetic geometries are predicted to be promising approaches to handle the power exhaust of future fusion devices. In order to understand the detachment process caused by volumetric losses in alternative divertor magnetic geometries, a Multi-Wavelength Imaging (MWI) diagnostic has recently been designed and built for the Mega Amp Spherical Tokamak Upgrade. The MWI diagnostic will simultaneously capture 11 spectrally filtered images of the visible light emitted from divertor plasmas and provide crucial knowledge for the interpretation of observations and modeling efforts. This paper presents the optical design, mechanical design, hardware, and test results of an 11-channel MWI system with a field of view of 40°. The optical design shows better than 5 mm FWHM spatial resolution at the plasma on all 11 channels across the whole field of view. The spread of angle of incidence on the surface of each filter is also analyzed to inform the bandwidth specification of the interference filters. The results of the initial laboratory tests demonstrate that a spatial resolution of better than 5 mm FWHM is achieved for all 11 channels, meeting the specifications required for accurate tomography. [ABSTRACT FROM AUTHOR]

Synchrotron radiation observed in a quiescent Tokamak ŕ Configuration Variable (TCV) runaway discharge is studied using filtered camera images targeting three distinct wavelength intervals. Through the tomographic simultaneous algebraic reconstruction technique (SART) procedure the high momentum, high pitch angle part of the spatial and momentum distribution of these relativistic particles is reconstructed. Experimental estimates of the distribution are important for verification and refinement of formation-, decay- and transport-models underlying runaway avoidance and mitigation strategy design. Using a test distribution it is demonstrated that the inversion procedure provides estimates accurate to within a few tens of percent in the region of phase-space contributing most to the synchrotron image. We find that combining images filtered around different parts of the emission spectrum widens the probed part of momentum-space and reduces reconstruction errors. Next, the SART algorithm is used to obtain information on the spatiotemporal runaway momentum distribution in a selected TCV discharge. The momentum distribution is found to relax towards an avalanche-like exponentially decaying profile. Anomalously high pitch angles and a radial profile increasing towards the edge are found for the most strongly emitting particles in the distribution.Pitch angle scattering by toroidal magnetic field ripple is consistent with this picture. An alternative explanation is the presence of high frequency instabilities in combination with the formation of a runaway shell at the edge of the plasma. [ABSTRACT FROM AUTHOR]

Detachment, an important mechanism for reducing target heat deposition, is achieved through reductions in power, particle and momentum; which are induced through plasma–atom and plasma–molecule interactions. Experimental research in how those reactions precisely contribute to detachment is limited. Both plasma–atom as well as plasma–molecule interactions can result in excited hydrogen atoms which emit atomic line emission. In this work, we investigate a new Balmer Spectroscopy technique for Plasma–Molecule Interaction—BaSPMI. This first disentangles the Balmer line emission from the various plasma–atom and plasma–molecule interactions and secondly quantifies their contributions to particle (ionisation and recombination) and power balance (radiative power losses). Its performance is verified using synthetic diagnostic techniques of both attached and detached TCV and MAST-U SOLPS-ITER simulations. We find that H2 plasma chemistry involving and/or H− can substantially elevate the Hα emission during detachment, which we show is an important precursor for Molecular Activated Recombination. An example illustration analysis of the full BaSPMI technique shows that the hydrogenic line series, even Lyα as well as the medium-n Balmer lines, can be significantly influenced by plasma–molecule interactions by tens ofpercent. That has important implications for using atomic hydrogen spectroscopy for diagnosing divertor plasmas. [ABSTRACT FROM AUTHOR]

In magnetic confinement thermonuclear fusion the exhaust of heat and particles from the core remains a major challenge. Heat and particles leaving the core are transported via open magnetic field lines to a region of the reactor wall, called the divertor. Unabated, the heat and particle fluxes may become intolerable and damage the divertor. Controlled 'plasma detachment', a regime characterized by both a large reduction in plasma pressure and temperature at the divertor target, is required to reduce fluxes onto the divertor. Here we report a systematic approach towards achieving this critical need through feedback control of impurity emission front locations and its experimental demonstration. Our approach comprises a combination of real-time plasma diagnostic utilization, dynamic characterization of the plasma in proximity to the divertor, and efficient, reliable offline feedback controller design. The exhaust of heat and particles is an important challenge in future nuclear fusion devices. Here the authors report the use of carbon emission as indicator for plasma detachment in a tokamak and its real-time feedback control. [ABSTRACT FROM AUTHOR]

Disruption mitigation remains a critical and unresolved issue for ITER. Measurement uncertainties preventing quantification of a system's efficacy remains a significant hurdle in producing and validating a viable disruption mitigation system. This study addresses this issue through the creation of a dataset on the ASDEX Upgrade tokamak targeted at developing analysis techniques to quantify mitigation that are applicable irrespective of the disruption mitigation system being studied. These experiments used a range of thermal energy fractions to address concerns for ITER from JET massive gas injection (MGI) experiments showing a decrease in efficacy with increasing thermal energy fraction. The dataset produced in this study used MGI valves in two toroidal locations. The high resolution foil bolometers and AXUV diode arrays were used to infer radiation emission profiles at varying toroidal distances from the injection location. The fueling efficiency of the two systems was found to be comparable and toroidal asymmetries over the entire disruption were found to be negligible. The AXUV diodes were cross-calibrated with the foil bolometers and used to estimate the thermal energy radiated and magnetic energy coupled to the vessel structure and coils. It was estimated that 75–95% of the thermal energy was radiated and an almost constant 60% of the total magnetic energy was coupled. Radiated energy fractions of 0.8–1.0 were calculated and no decrease as a function of thermal energy fraction was found. A ± 20% variation in the coupled magnetic energy was explored and it did not alter this trend. [ABSTRACT FROM AUTHOR]

Synchrotron radiation observed from runaway electrons (REs) in tokamaks depends upon the position and size of the RE beam, the RE energy and pitch distributions, as well as the location of the observer. We show experimental synchrotron images of a vertically moving RE beam sweeping past the detector in the Tokamak ŕ Configuration Variable (TCV) tokamak and compare it with predictions from the synthetic synchrotron diagnostic Soft. This experimental validation lends confidence to the theory underlying the synthetic diagnostics which are used for benchmarking theoretical models of and probing runaway dynamics. We present a comparison of synchrotron measurements in TCV with predictions of kinetic theory for runaway dynamics in uniform magnetic fields. We find that to explain the detected synchrotron emission, significant non-collisional pitch angle scattering as well as radial transport of REs would be needed. Such effects could be caused by the presence of magnetic perturbations, which should be further investigated in future TCV experiments. [ABSTRACT FROM AUTHOR]

Fast-particle driven Alfvén Eigenmodes have been observed in low-collisionality discharges with off-axis neutral beam injection (NBI), electron cyclotron resonance heating (ECRH) and a reduced toroidal magnetic field. During NBI and ECRH, toroidicity induced Alfvén Eigenmodes (TAEs) appear in frequency bands close to 200 kHz and energetic-particle-induced geodesic acoustic modes (EGAMs) are observed at about 40 and 80 kHz. When turning off ECRH in the experiment, those beam-driven modes disappear which can be explained by a modification of the fast-ion slowing down distribution. In contrast, coherent fluctuations close to the frequency of the beam-driven TAEs are present throughout the experiment. The modes are even observed during ohmic plasma conditions, which clearly demonstrates that they are not caused by fast particles and suggests an alternative drive, such as turbulence. The mode-induced fast-ion transport has been found to be weak and marginal in terms of the fast-ion diagnostic sensitivities. Measurements of the plasma stored energy, neutron rates, neutral particle fluxes and fast-ion D-alpha spectroscopy show good agreement with neoclassical modelling results from TRANSP. This is further supported by a similarly good agreement between measurement and modelling in cases with and without ECRH and therefore with and without the modes. Instead, a significant level of charge exchange losses are predicted and observed which generate a bump-on-tail fast-ion distribution function that can provide the necessary free energy to EGAMs. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to compare clinical and laximetric results in chronic, isolated posterior cruciate ligament (PCL) rupture repairs, using either a hamstring graft or an artificial ligament (ligament advanced reinforcement system (LARS®)).Methods: Sixteen patients presenting with an isolated unilateral PCL rupture were included in this retrospective study. Initially, eight underwent a PCL reconstruction using a hamstring tendon autograft (hamstring group), and over a later period, eight further patients underwent a reconstruction using an artificial ligament with a new procedure.Results: Fifteen patients were male and one female, with an average age of 29.3 years. All patients were operated on within an average time of 18 months post-injury. Pre-operative posterior laxity was equivalent (p = 0.309), 18.25 mm on average for the hamstring group and 18.75 mm for the LARS group. With an average follow-up of 24 months, residual posterior laxity was significantly improved, decreasing from 18.25 to 7.37 mm for the hamstring group (p < 0.05) with a median at 7.5 mm and from 18.75 to 5.25 mm for the LARS group (p < 0.05) with a median at 5 mm. The improvement in laxity for the hamstring group was 60% and 71.5% for the LARS group. The LARS group compares favourably (p = 0.003 and 0.01). Tegner activity level improved significantly following ligamentoplasty, with no difference between the two groups (p = 0.4). Likewise, there was no significant difference in the Lysholm and IKDC scores between the two groups (p = 0.4).Conclusion: The initial hypothesis of this study was proven correct. Nevertheless, a longer term study is necessary to assess the consequences of residual laxity in hamstring grafts and the long-term behaviour and tolerance of the LARS artificial ligament. [ABSTRACT FROM AUTHOR]

This work presents a novel, real-time capable, 10-channel Multispectral Advanced Narrowband Tokamak Imaging System installed on the TCV tokamak, MANTIS. Software and hardware requirements are presented together with the complete system architecture. The image quality of the system is assessed with emphasis on effects resulting from the narrowband interference filters. Some filters are found to create internal reflection images that are correlated with the filters' reflection coefficient. This was measured for selected filters where significant absorption (up to 65% within ∼70 nm of the filter center) was measured. The majority of this was attributed to the filter's design, and several filters' performance is compared. Tailored real-time algorithms exploiting the system's capabilities are presented together with benchmarks comparing polling and event based synchronization. The real-time performance is demonstrated with a density ramp discharge performed on TCV. The behavior of spectral lines' emission from different plasma species and their interpretation are qualitatively described. [ABSTRACT FROM AUTHOR]

Introduction: The aim of this study was to assess the differential laxity after reconstruction of the anterior cruciate ligament (ACL) by the TLS® technique using a single tendon, the semitendinosus in four-strand graft, compared with the hamstring technique which uses both the gracilis and semitendinosus. We hypothesised that this surgical technique would provide post-surgical differential laxity measurements at least as good as those of the hamstring technique. Materials and methods: We carried out a prospective monocentric study on patients undergoing unilateral anterior cruciate ligament repair between December 2014 and June 2016. All patients were followed up for at least 12 months. The series compares 61 patients operated on using the TLS® technique by the same surgeon, with 33 patients operated on using the hamstring technique by a second surgeon. The main objective of the study was to compare the post-operative differential laxity, measured using the KT1000, between the two techniques. Results: There was no significant difference in the patients' epidemiological characteristics and pre-operative scores between the two groups. Average pre-operative differential laxity was 6.5 mm ± 2.1 (min 3; max 12) in the TLS group and 6.4 mm ± 2.0 (min 0; max 11) in the hamstring group, with no statistically significant difference. The average post-operative difference in laxity was − 0.1 mm ± 1.9 (min − 5; max 4) in the TLS group and 0.3 mm ± 2.0 (min − 7; max 5) in the hamstring group. Again, no significant difference was observed between groups. Discussion: This study demonstrates a level of post-operative differential laxity control using TLS comparable with that of the ACL reconstruction technique using a hamstring graft with preserved tibial insertion. Level of evidence: II, prospective cohort study. [ABSTRACT FROM AUTHOR]

Focuses on the use of collective Thomson scattering to provide local ion temperature measurements of the plasma in the tokamak chauffage Alfvén tokamak. Description of the apparatus used in the experiment;Technique used to measure system noise temperature of the heterodyne detection system.

This Letter reports the design, fabrication and characterisation of a new differential linear driver, fabricated in the III-V Lab 0.7- ${\rm \mu }{\rm m}$μm emitter width indium phosphide (InP) double heterojunction bipolar transistor (DHBT) technology. Large-signal electrical characterisation shows 80-GBd symbol-rate four-level pulse amplitude (PAM-4) modulation conjugated with a driver output swing of 3-Vppdiff and a 0.74-W power consumption. Thus resulting in a 1.22-GBd driving efficiency, the highest in over 70-GBd drivers' state-of-the-art, at that date. Accordingly, S-parameter measurements of the standalone linear driver exhibit the highest gain-bandwidth product of 556 GHz, in that current state-of-the-art. [ABSTRACT FROM AUTHOR]

A computer simulation technique is applied to the modelling of Balmer line shapes in dense divertor conditions. The spectral profile of lines with a high principal quantum number n is sensitive to Stark broadening and can be used as a density diagnostic. In contrast, an analysis of the shape of low or moderate n lines such as Dα (n = 3), Dβ (n = 4), and Dγ (n = 5) is more intricate because the Stark effect is weaker and can compete with thermal Doppler broadening. We examine this issue and address the relative contribution of the Stark and Doppler effects on the first Balmer lines. Analyses of experimental spectra are performed. [ABSTRACT FROM AUTHOR]

A large database of reciprocating probe data from the edge plasma of TCV (Tokamak à Configuration Variable) is used to test the radial velocity scalings of filaments from analytical theory [Myra et al., Phys. Plasmas 13, 112502 (2006)]. The measured velocities are mainly scattered between zero and a maximum velocity which varies as a function of size and collisionality in agreement with the analytical scalings. The scatter is consistent with mechanisms that tend to slow the velocity of individual filaments. While the radial velocities were mainly clustered between 0.5 and 2 km/s, a minority reached outward velocities as high as 5 km/s or inward velocities as high as −4 km/s. Inward moving filaments are only observed in regions of high poloidal velocity shear in discharges with B × ∇B away from the X-point, a new finding. The filaments have diameters clustered between 3 and 11 mm, and normalized sizes a ̂ clustered between 0.3 and 1.1, such that most filaments populate the resistive-ballooning regime; therefore, most of the filaments in TCV have radial velocities with little or no dependence on collisionality. Improvements in cross-correlation techniques and conditional averaging techniques are discussed which reduce the sizes determined for the largest filaments, including those larger than the scrape-off layer. [ABSTRACT FROM AUTHOR]

Heat flux profiles inferred from a reciprocating probe at the outer midplane of the TCV tokamak during inner wall limited discharges feature radial fall-off lengths that shorten near the last closed flux surface (LCFS) consistent with the so-called narrow feature. The narrow feature is significantly wider on the outboard side compared with that measured on the inner wall by infrared thermography, so it is difficult to discern from the main scrape-off layer feature. After small shifts were applied for alignment, the fraction of the power contained in the narrow feature matches between inboard and outboard measurements, and they scale together with plasma current Ip, suggesting that we are observing the same phenomenon. The outboard side fall-off length within the narrow feature is found to scale closely with the radial correlation length of the edge turbulence as expected if the narrow feature arises due to radially sheared E×B flows. This is found to hold true even for cases where the narrow feature is weak and the fall-off lengths are approaching that of the far scrape-off layer. After the small shifts for alignment, non-zero floating potential profiles were found to match between inboard and outboard sides. A simple model of polarization and diamagnetic cross-field currents is described, which is consistent with the shape of these floating potential profiles. The model predicts that the floating potential at the LCFS must be negative, which supports the argument to shift the upstream measurements. The predicted currents are also consistent with the E×B flows believed to cause the narrow feature. The model is used to predict the magnitude of the floating potential of the LCFS, and the results are found to match measurements for all values of Ip. This paper therefore demonstrates consistency between the measurements of the narrow feature on the inboard and outboard sides of the plasma, as well as consistency between the measurements, non-linear turbulence simulations, and analytical models of the narrow feature arising from sheared E×B flows. [ABSTRACT FROM AUTHOR]

This paper presents the integration of an acquisition and computing unit capable of acquiring and processing fast magnetic signals in real time in the control system of the tokamak à configuration variabile tokamak. All aspects of system integration and testing are reported, leading to testing of the system on plasma discharges. An example of a real-time analysis algorithm designed for detecting and classifying neoclassical tearing modes plasma instabilities is also described. [ABSTRACT FROM AUTHOR]

In this Letter, the authors report on the design, optimisation and electrical measurements of a new fully integrated multiplexing selector fabricated in 0.7‐µm indium phosphide (InP) double‐heterojunction bipolar transistor technology. All parts of the circuit were optimised to obtain 200‐Gbit/s class of operation. They present electrical performances at 140 and to a record speed of 212 Gbit/s, highlighting their respective measurement challenges. The power consumption of the circuit is 0.5 and 0.8 W for a differential output amplitude of 240 and 730 mV, respectively. This selector has been successfully used as modulator driver in optical transmission experiments up to 204 Gbit/s. [ABSTRACT FROM AUTHOR]

Purpose: The goal of this article is to present our experience on navigation for osteotomies around the knee and especially osteotomies for coronal deformities. The first computer-assisted osteotomy was performed in March 2001 and since that time more than 1000 osteotomies have been performed in our department.Methods: All the osteotomies were performed with the Orthopilot® device (B-Braun-Aesculap, Tuttlingen, Germany). The main indication was for genu varum deformities but several cases were operated for genu valgum. The surgical procedure as well as the indications and the rationale for each osteotomy (high tibial osteotomy-HTO, double-level osteotomy-DLO, femoral osteotomy-FO) are addressed in the article.Results: The results are focused on several papers published by the authors since more than 10 years. Regarding HTO for genu varum, the preoperative goal (HKA angle: 184° ± 2°) was reached in 96 % of cases and the difference was statistically significant compared to the non-navigated series (71 %: p < 0.05). Regarding DLO for genu varum, the preoperative goal was reached in 92.7 % for the HKA angle and in 88.1 % for the medial proximal tibial mechanical angle (MPTMA). Regarding genu valgum deformity, the preoperative goal was achieved in 86.2 % of cases for the HKA angle and 100 % of cases for the MPTMA.Conclusion: According to these results, one can say that, regardless the type of osteotomy, the procedure is reliable, reproducible and accurate. Since 15 years, all the osteotomies around the knee are navigated in our department. Provided that one uses a reproducible radiograph protocol, navigation allows to perform double-level osteotomies, both for genu varum and genu valgum, with optimal accuracy in order to avoid oblique joint line, which will be difficult to revise to TKA.Level Of Evidence: IV. [ABSTRACT FROM AUTHOR]

Free boundary magnetohydrodynamic equilibrium states with spontaneous three dimensional deformations of the plasma-vacuum interface are computed for the first time. The structures obtained have the appearance of saturated ideal external kink/peeling modes. High edge pressure gradients yield toroidal mode number n = 1 corrugations for a high edge bootstrap current and larger n distortions when this current is small. Deformations in the plasma boundary region induce a nonaxisymmetric Pfirsch-Schlüter current driving a field-aligned current ribbon consistent with reported experimental observations. A variation in the 3D equilibrium confirms that the n = 1 mode is a kink/peeling structure. We surmise that our calculated equilibrium structures constitute a viable model for the edge harmonic oscillations and outer modes associated with a quiescent H-mode operation in shaped tokamak plasmas. [ABSTRACT FROM AUTHOR]

Modern Tokamaks have evolved from the initial axisymmetric circular plasma shape to an elongated axisymmetric plasma shape that improves the energy confinement, which is one of the key factors to improve fusion reactor performance. However, the elongated plasma cross section introduces a vertical instability that requires a real-time feedback control loop to stabilize the plasma vertical position and velocity. At the Tokamak à Configuration Variable (TCV) in-vessel poloidal field coils driven by fast switching power supplies are used to stabilize highly elongated plasmas. TCV plasma experiments have used a PID algorithm based controller to correct the plasma vertical position. In late 2013 experiments a new optimal real-time controller was tested improving the stability of the plasma. This contribution describes the new optimal real-time controller developed. The choice of the model that describes the plasma response to the actuators is discussed. The high order model that is initially implemented needs the application of a mathematical order reduction and the validation of the new reduced model. The lower order model is used to derive the time optimal control law. A new method for the construction of the switching curves of a bang-bang controller is presented that is based on the state-space trajectories that optimize the time to target of the system. The final control algorithm and its implementation are described and preliminary experimental results are discussed. [ABSTRACT FROM AUTHOR]

Recent theoretical work predicts intrinsic toroidal rotation in the tokamak edge to depend strongly on the normalized major radial position of the X-point. With this motivation, we conducted a series of Ohmic L-mode shots on the Tokamak à Configuration Variable, moving the X-point from the inboard to the outboard edge of the last closed flux surface in both lower and upper single null configurations. The edge toroidal rotation evolved from strongly co-current for an inboard X-point to either vanishing or counter-current for an outboard X-point, in agreement with the theoretical expectations. The whole rotation profile shifted roughly rigidly with the edge rotation, resulting in variation of the peak core rotation by more than a factor of two. Core rotation reversals had little effect on the edge rotation. Edge rotation was slightly more counter-current for unfavorable than favorable ∇B drift discharges. [ABSTRACT FROM AUTHOR]

The object of this review is to summarize the achievements of research on the Alcator C-Mod toka-mak [Hutchinson et al., Phys. Plasmas 1, 1511 (1994) and Marmar, Fusion Sci. Technol. 51, 261 (2001)] and to place that research in the context of the quest for practical fusion energy. C-Mod is a compact, high-field tokamak, whose unique design and operating parameters have produced a wealth of new and important results since it began operation in 1993, contributing data that extends tests of critical physical models into new parameter ranges and into new regimes. Using only high- power radio frequency (RF) waves for heating and current drive with innovative launching struc-tures, C-Mod operates routinely at reactor level power densities and achieves plasma pressures higher than any other toroidal confinement device. C-Mod spearheaded the development of the vertical-target divertor and has always operated with high-Z metal plasma facing components-- approaches subsequently adopted for ITER. C-Mod has made ground-breaking discoveries in diver-tor physics and plasma-material interactions at reactor-like power and particle fluxes and elucidated the critical role of cross-field transport in divertor operation, edge flows and the tokamak density limit. C-Mod developed the I-mode and the Enhanced Da H-mode regimes, which have high per-formance without large edge localized modes and with pedestal transport self-regulated by short-wavelength electromagnetic waves. C-Mod has carried out pioneering studies of intrinsic rotation and demonstrated that self-generated flow shear can be strong enough in some cases to significantly modify transport. C-Mod made the first quantitative link between the pedestal temperature and the H-mode's performance, showing that the observed self-similar temperature profiles were consistent with critical-gradient-length theories and followed up with quantitative tests of nonlinear gyroki-netic models. RF research highlights include direct experimental observation of ion cyclotron range of frequency (ICRF) mode-conversion, ICRF flow drive, demonstration of lower-hybrid current drive at ITER-like densities and fields and, using a set of novel diagnostics, extensive validation of advanced RF codes. Disruption studies on C-Mod provided the first observation of non-axisymmetric halo currents and non-axisymmetric radiation in mitigated disruptions. A summary of important achievements and discoveries are included [ABSTRACT FROM AUTHOR]

Transport analyses using first-principle turbulence codes and 1 1/2-D transport codes usually study radial transport properties between the tokamak plasma magnetic axis and a normalized minor radius around 0.8. In this region, heat transport shows significantly stiff properties resulting in temperature scalelength values (R=LT) that are relatively independent of the level of the radial heat flux. We have studied experimentally in the tokamak á configuration variable [F. Hofmann et al., Plasma Phys. Controlled Fusion 36, B277 (1994)] the radial electron transport properties of the edge region, close to the last closed flux surface, namely, between ρv=√V/Vedge ρ = 0:8 to 1. It is shown that electron transport is not stiff in this region and high R=LTe values (~20-40) can be attained even for L-mode confinement. We can define a "pedestal" location, already in L-mode regimes, where the transport characteristics change from constant logarithmic gradient, inside ρV=0.8, to constant gradient between 0.8 and 1.0. In particular, we demonstrate, with well resolved Te and ne profiles, that the confinement improvement with plasma current Ip, with or without auxiliary heating, is due to this non-stiff edge region. This new result is used to explain the significant confinement improvement observed with negative triangularity, which could not be explained by theory to date. Preliminary local gyrokinetic simulations are now consistent with an edge, less stiff, region that is more sensitive to triangularity than further inside. We also show that increasing the electron cyclotron heating power increases the edge temperature inverse scalelength, in contrast to the value in the main plasma region. The dependence of confinement on density in ohmic plasmas is also studied and brings new insight in the understanding of the transition between linear and saturated confinement regimes, as well as of the density limit and appearance of a 2/1 tearing mode. The results presented in this paper provide an important new perspective with regards to radial transport in tokamak plasmas which goes beyond L-mode plasmas and explains some previous puzzling results. It is proposed that understanding the transport properties in this edge non-stiff region will also help in understanding the improved and high confinement edge properties. [ABSTRACT FROM AUTHOR]