Overview of the TCV tokamak experimental programme

The tokamak a configuration variable (TCV) continues to leverage its unique shaping capabilities, flexible heating systems and modern control system to address critical issues in preparation for ITER and a fusion power plant. For the 2019-20 campaign its configurational flexibility has been enhanced with the installation of removable divertor gas baffles, its diagnostic capabilities with an extensive set of upgrades and its heating systems with new dual frequency gyrotrons. The gas baffles reduce coupling between the divertor and the main chamber and allow for detailed investigations on the role of fuelling in general and, together with upgraded boundary diagnostics, test divertor and edge models in particular. The increased heating capabilities broaden the operational regime to include T (e)/T (i) similar to 1 and have stimulated refocussing studies from L-mode to H-mode across a range of research topics. ITER baseline parameters were reached in type-I ELMy H-modes and alternative regimes with \u27small\u27 (or no) ELMs explored. Most prominently, negative triangularity was investigated in detail and confirmed as an attractive scenario with H-mode level core confinement but an L-mode edge. Emphasis was also placed on control, where an increased number of observers, actuators and control solutions became available and are now integrated into a generic control framework as will be needed in future devices. The quantity and quality of results of the 2019-20 TCV campaign are a testament to its successful integration within the European research effort alongside a vibrant domestic programme and international collaborations

Physics research on the TCV tokamak facility: from conventional to alternative scenarios and beyond

The research program of the TCV tokamak ranges from conventional to advanced-tokamak scenarios and alternative divertor configurations, to exploratory plasmas driven by theoretical insight, exploiting the device’s unique shaping capabilities. Disruption avoidance by real-time locked mode prevention or unlocking with electron-cyclotron resonance heating (ECRH) was thoroughly documented, using magnetic and radiation triggers. Runaway generation with high-Z noble-gas injection and runaway dissipation by subsequent Ne or Ar injection were studied for model validation. The new 1 MW neutral beam injector has expanded the parameter range, now encompassing ELMy H-modes in an ITER-like shape and nearly non-inductive H-mode discharges sustained by electron cyclotron and neutral beam current drive. In the H-mode, the pedestal pressure increases modestly with nitrogen seeding while fueling moves the density pedestal outwards, but the plasma stored energy is largely uncorrelated to either seeding or fueling. High fueling at high triangularity is key to accessing the attractive small edge-localized mode (type-II) regime. Turbulence is reduced in the core at negative triangularity, consistent with increased confinement and in accord with global gyrokinetic simulations. The geodesic acoustic mode, possibly coupled with avalanche events, has been linked with particle flow to the wall in diverted plasmas. Detachment, scrape-off layer transport, and turbulence were studied in L- and H-modes in both standard and alternative configurations (snowflake, super-X, and beyond). The detachment process is caused by power ‘starvation’ reducing the ionization source, with volume recombination playing only a minor role. Partial detachment in the H-mode is obtained with impurity seeding and has shown little dependence on flux expansion in standard single-null geometry. In the attached L-mode phase, increasing the outer connection length reduces the in–out heat-flow asymmetry. A doublet plasma, featuring an internal X-point, was achieved successfully, and a transport barrier was observed in the mantle just outside the internal separatrix. In the near future variable-configuration baffles and possibly divertor pumping will be introduced to investigate the effect of divertor closure on exhaust and performance, and 3.5 MW ECRH and 1 MW neutral beam injection heating will be added

Prevalence and determinants of low birth weight in Jimma zone, Southwest Ethiopia

Objectives: To assess the prevalence and determinants of low birth weights (LBW). Design: A cross-sectional descriptive study. Setting: Four health centers (Jimma, Agaro, Asendabo and Shebe) within 5-50 km radius from Jimma University and Jimma University hospital from September 1, 2002 to March 30, 2003. Subjects: Mothers with newborns delivered in the above institutions and those delivered at home and received care within the first 24 hours after delivery in the above health care settings. Results: A total of 145 (22.5 %) of the newborns were LBW. Mothers residing in the urban setting had higher risk of delivering LBW babies and the difference was statistically significant (p = 0.00). Analysis of maternal obstetric history revealed that those mothers who delivered before 37 weeks of gestation, had weight loss, and who did not receive additional diet during pregnancy had higher risk of delivering LBW babies and the difference was statistically significant (p = 0.01, 0.00, 0.00) respectively. Similarly, those who had multiple gestations had a higher risk of delivering LBW babies and the difference was statistically significant (p = 0.00). Conclusions: Despite the fact that the method of sampling used in this study has its own limitation, the prevalence of LBW in this study was relatively higher than the reported current estimate of LBW in Ethiopia. Therefore, it is recommended that special attention should be given to adequate rest and additional diet during pregnancy and making antenatal services available and accessible to all pregnant women. East African Medical Journal Vol. 83(7) 2006: 366-37

PREVALENCE AND DETERMINANTS OF LOW BIRTH WEIGHT IN JIMMA ZONE, SOUTHWEST ETHIOPIA

Objectives: To assess the prevalence and determinants of low birth weights (LBW).Design: A cross-sectional descriptive study.Setting: Four health centers (Jimma, Agaro, Asendabo and Shebe) within 5-50 km radius from Jimma University and Jimma University hospital from September 1, 2002 to March 30, 2003.Subjects: Mothers with newborns delivered in the above institutions and those delivered at home and received care within the first 24 hours after delivery in the above health care settings.Results: A total of 145 (22.5 %) of the newborns were LBW. Mothers residing in the urban setting had higher risk of delivering LBW babies and the difference was statistically significant (p = 0.00). Analysis of maternal obstetric history revealed that those mothers who delivered before 37 weeks of gestation, had weight loss, and who did not receive additional diet during pregnancy had higher risk of delivering LBW babies and the difference was statistically significant (p = 0.01, 0.00, 0.00) respectively. Similarly, those who had multiple gestations had a higher risk of delivering LBW babies and the difference was statistically significant (p = 0.00).Conclusions: Despite the fact that the method of sampling used in this study has its own limitation, the prevalence of LBW in this study was relatively higher than the reported current estimate of LBW in Ethiopia. Therefore, it is recommended that special attention should be given to adequate rest and additional diet during pregnancy and making antenatal services available and accessible to all pregnant women

Archaeology and Geomagnetism: Investigating the Earth's Magnetic Field in Italy during the Neolithic Period. New Data from the Portonovo Archaeological Site (Marche, Italy)

Archaeomagnetic data from ancient baked clays is a precious source of information about the past variations of the Earth's magnetic field. Thanks to archaeomagnetic records from well dated archaeological artefacts it is possible to reconstruct the geomagnetic field variations in the past and better understand its behaviour. On the other hand, once a detailed secular variation path is established for a certain area, reliable archaeomagnetic dating is possible. In order to enrich the Italian reference database and extend it back in time, we present here the results of an archaeomagnetic study carried out on three Neolithic ovens excavated at the archaeological site of Portonovo (Marche, Italy