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The TCV tokamak ( R = 0.88 m, κ = 2.5, are produced at low normalized current using far off-axis EC heating (ECH) and ECCD to broaden the current profile. Third harmonic heating is used to heat the plasma center where the second harmonic is in cut-off. Both second and third harmonic heating are used to heat H-mode plasmas, at the edge and center, respectively. The ELM frequency is decreased by the additional power but in separate experiments can be controlled by locking to an external perturbation current in the internal coils of TCV. Spatially resolved current profiles are measured at the inner and outer divertor targets by Langmuir probe arrays during ELMs. The strong, reasonably balanced currents are thought to be thermoelectric in origin.

Evidence from injection into the TCV device of laser ablated, non-recycling silicon impurities shows that the transport of impurities confinement can be remarkably different from that of energy. The ratio of impurity to energy confinement times ranges from near unity in Ohmic discharges to 5 in the presence of high power ECCD. In Ohmic discharges in deuterium, above a threshold of density and of safety factor near q(95) = 4.5, the impurity confinement time increases abruptly by a factor of 2 and is sometimes accompanied by indefinite retention of non-recycling impurities within the sawtooth mixing radius.

The operating space of the TCV tokamak has been extended to higher elongation, kappa = 2.8, and higher normalized current, I-N = I-p/aB = 3.6MA/mT, than were previously attainable. This has been achieved by optimizing the parameters of the vertical position control system and by optimizing the plasma shape. Experimental current and beta limits were found to be consistent with ideal MHD stability calculations, using measured plasma shapes and profiles. The sawtooth period was measured as a function of elongation and sawtooth oscillations are found to disappear, at high elongation, when the internal inductance drops below l(i) similar to 0.69. MHD events at high elongation have been analysed, using magnetic fluctuation measurements. The electron energy confinement time at high elongation, 2.2 < kappa < 2.7, shows a strong dependence on density and power flux through the plasma surface, but no statistically significant dependence on K. Finally, we have applied off-axis, second harmonic, X-mode electron cyclotron resonance heating (ECRH) in order to flatten the current profile and improve vertical stability. This gave access to previously inaccessible domains in kappa-IN space.

The extreme shaping capabilities of the TCV tokamak have been used to investigate the effect of plasma geometry on the confinement of non-recycling trace impurities injected by means of the laser blow-off technique. The progression of the injected silicon in the core of TCV Ohmic limiter plasmas was followed by the 200-channel soft x-ray (SXR) photodiode array with good spatial and temporal resolution. The results show that the plasma triangularity and elongation play an important role in the impurity confinement time, tau(imp). Remarkably, the increase of elongation from kappa = 1.6 to 2.3 produces a threefold reduction of tau(imp) while the electron energy confinement time, tau(Ee), remains almost constant. tau(imp) is fairly constant in the triangularity scan for delta > 0.2, while there is a marked increase for lower values, leading to tau(imp) > 100 ms for negative triangularities. The increase of the toroidal magnetic field, B-T, from B-T = 0.92 to 1.47 T produces a decrease in the confinement time by almost a factor of 2. Simulation of the evolution of the line-integrated SXR signals, performed by the one-dimensional code STRAHL, provided both central and peripheral values of the transport coefficients together with estimates of the radial profiles. The simulations show that anomalous transport is dominant over neoclassical transport, except near the plasma centre. Interestingly, the convective velocity is positive (outwardly directed) in all limiter cases.

This paper presents experimental results on the accessibility and the properties of plasmas with improved confinement in TCV. First, the H-mode threshold power is measured in Ohmic plasmas. Above an Ohmic threshold density, the threshold power increases with the density. A lower threshold density is found when additional electron cyclotron heating (ECH) is applied. At these low densities, the threshold power increases dramatically with decreasing density. Only a small fraction of the wide operational domain leading to the Ohmic H-mode is found to lead to a stationary regime with edge localized modes (ELMs). The ELMs have an irregular frequency, but in TCV they can be triggered by an external magnetic perturbation that induces a rapid vertical movement of the plasma. With this perturbation, the ELM frequency can be increased. The ELM triggering mechanism is provided by the vertical movement of the plasma away from the X-point of a single null configuration. This movement induces a positive current at the plasma edge, and we deduce that the ELMs are being controlled by this modification of the plasma edge current. Electron internal transport barriers (eITBs) are produced deep in the plasma during the stationary phase of TCV discharges. Different scenarios of ECH or selectron cyclotron current drive (ECCD) at different radial locations have been used to obtain eITBs with and without inductively driven current. The eITBs are characterized by steep electron temperature gradients, high confinement improvement and a large fraction of bootstrap current. In plasmas with fully non-inductively driven current the size and the strength of the eITB are controlled by the location of the power deposition and by the co- or counter-direction of the central ECCD. Finally, a small inductive perturbation of an otherwise non-inductively driven plasma current profile progressively shrinks the eITB, confirming the link between current profiles and eITBs.

Objective: To explore the association between perceived sleep quality and participation in people with spinal cord injury (SCI). Design: Cross-sectional study. Setting: Spinal unit at the Città della Salute e della Scienza University Hospital of Turin, Italy. Participants: From May to July 2019, 55 consecutive outpatients were recruited. Outcome measures: A set of structured questionnaires was administered. It included sociodemographic data, the Pittsburgh Sleep Quality Index, the Utrecht Scale for Evaluation of Rehabilitation-Participation, the Spinal Cord Independence Measure Self-Report, the Short Form version 12.2, and the Hospital Anxiety and Depression Scale. T-tests were used to highlight differences between participation and participant characteristics. Bivariate analyses and linear regressions were performed to identify associations between sleep quality and participation. Results: Differences in participation occurred mainly in individuals with a higher level of injury, caregiver dependency, and lower functional level. Participants reporting better sleep quality had more frequent (r = –0.36, P < 0.01), less restricted (r = –0.32, P < 0.05), and more satisfactory participation (r = –0.33, P < 0.01). Linear regression analyses showed that poor sleep quality was significantly associated with reduced participation frequency (β = –0.30, P = 0.03) and less satisfaction with participation (β = –0.49, P < 0.001). Moreover, age, number of hours slept at night, and time since injury were associated with satisfaction with participation. Conclusions: An association was found between sleep quality and participation in people with SCI. Given the high prevalence of sleep problems and their association with all dimensions of participation, the promotion of sleep quality should be encouraged because it may positively affect participation.