On non-zero space average density perturbation effects in tokamak plasma reflectometer signals

12th International Congress on Plasma Physics, 25-29 October 2004, Nice (France)The effects of the non-zero average density perturbation on phase and amplitude measured by reflectometry are presented. The non-zero average density perturbation on the phase variation can be seen as an index effect as soon as the shape of the density perturbation does not introduce spectral effects. Amplitude modulation in time follows generally the properties of the cut-off layer seen as a mirror but some specific situations produce a time modulation two times higher than the input time variation of the density perturbation as observed in Tore Supra. The introduction of secondary cut-off can exhibit this effect as shown in 2D simulations

Assessment of the functionality of hand-pump boreholes drilled through the Basic Services Fund, South Sudan

After decades of civil war, the Basic Services Fund (BSF), with DFID as lead donor, was a major contributor to the reconstruction efforts of the Government of South Sudan to develop its basic services. Between 2006 and 2012, 29 NGOs received grants for WASH projects mostly for drilling or rehabilitating hand-pump boreholes. Over 6 years, 578 new hand-pump boreholes were drilled. Borehole functionality is however a major challenge in South Sudan: The National Water Policy states that only 30-50 % of the boreholes are functional at any time. To quantify the real outcomes of the BSF and assess the impact of the sustainability-focused monitoring of the BSF Secretariat, a status review was conducted on all drilling activities carried out since 2006, one of the components being to execute a functionality assessment of all BSF boreholes. This article describes the conceptual framework, the methodology as well as the main results of the assessment

Adopting locally appropriate WASH solutions: a case study of rock catchment systems in South Sudan

Sustainability of water infrastructures is a well-known challenge especially in post-conflict countries, where communities have been used to quick and emergency-focused aid. This article presents a case study on how sustainability can be positively influenced by opting for locally-appropriate technologies and by involving communities in its selection. Considering the abundant rainfall and the presence of rock outcrops in some parts of South Sudan, rock catchment systems are locally-appropriate solutions and good alternatives to the more common hand-pump boreholes. In Eastern Equatoria State, Caritas Switzerland successfully constructed eight rock catchment systems. The potential of using runoff water from rock outcrops to ease communities’ water situation and the cost-effectiveness and appropriateness of this technology has generated a lot of interests among communities, local government and other stakeholders, leading surrending communities with similar geological conditions to request for a similar system

Plasma turbulence measured by fast sweep reflectometry on TORE SUPRA

Traditionally devoted to electron density profile measurement we show that fast frequency sweeping reflectometry technique can bring valuable and innovative measurements onto plasma turbulence. While fast frequency sweeping technique is traditionally devoted to electron density radial profile measurements we show in this paper how we can handle the fluctuations of the reflected signal to recover plasma density fluctuation measurements with a high spatial and temporal resolution. Large size turbulence related to magneto-hydrodynamic (MHD) activity and the associated magnetic islands can be detected. The radial profile of the micro-turbulence, which is responsible for plasma anomalous transport processes, is experimentally determined through the fluctuation of the reflected phase signal.Comment: 12th International Congress on Plasma Physics, 25-29 October 2004, Nice (France

Building community WASH resilience: the case study of a rock catchment system in Marsabit County, Kenya

Implementing a rock catchment project entails a myriad of approaches and technological measures. The choice of approaches and technologies are a product of processes driven by the organisational culture, capacity and strategic priorities of the implementing development organisation. The approaches and technologies employed by the development agencies with the objective of improving water services are expected to align to the sector regulations. This expectation has not been entirely realised. At a time when climate risks have markedly increased, Caritas Switzerland in its effort to achieve sustainable water services at the community level, has employed technologies and approaches with impressive results. This has been possible through consolidating lessons learnt incrementally. This paper examines success features observed during and after the implementation of a drought resilience project by Caritas Switzerland in partnership with Ndikir community in Marsabit County, Kenya in 2014/15

From awareness raising to sustainable behaviour change in school: the WASH in school road map

Development organisations working in the WASH sector tend to focus on their preferred methodologies for Hygiene and Sanitation (H&S) promotion, while the sustainability of an intervention depends much more on how the methodology is implemented and whether an enabling environment is in place. In 2014, Caritas Switzerland in Kenya started a learning and critical review process on how to improve its WASH in school interventions to finally make the step from raising students’ awareness on good H&S practices to sustainable behaviour change. As a result of this process, a number of lessons on how to foster the enabling environment were learned, based on which the WASH in school road map was developed. This article presents, for each phase of the WASH in school road map, the main lessons learned and how they have been implemented in Kenya

Plasma Dynamics

Contains reports on seventeen research projects split into two sections.National Science Foundation (Grant ENG77-00340)U. S. Energy Research and Development Administration (Contract E(11-1)-2766)U. S. Energy Research and Development Administration (Contract EY-76-S-02-2766)U. S. Air Force - Office of Scientific Research (Grant AFOSR-77-3143)U. S. Department of Energy (Grant EG-77-G-01-4107

Plasma Dynamics

Contains research objectives and summary of research on nineteen research projects split into five sections.National Science Foundation (Grant ENG75-06242-A01)U.S. Energy Research and Development Administration (Contract E(11-1)-2766)U.S. Air Force - Office of Scientific Research (Grant AFOSR-77-3143)U.S. Energy Research and Development Administration (Contract EY-76-C2-02-3070.*000

Formation of spiral structures and radial convection in the edge region of a magnetized rotating plasma

The rotation of a cylindrical plasma column in a magnetic field has been studied in the linear section of the new plasma device Mistral. Under suitable conditions we observe a transition to a turbulent regime characterized by strong, bursty fluctuations at the edge of the column. The detection and the study of the spatio-temporal evolution of structures in the turbulent regime have been performed by means of a new enhanced conditional sampling technique. We have collected evidence of the development of a bent tail emanating from the plasma column. The charged particles inside the structure move along a spiral trajectory resulting in a net radial convection of the plasma to the walls. We show experimentally that a poloidal electric field is present inside the structures leading to the observed outwards radial E × B drift, in agreement with the expectations of recent and past theoretical works

Variation en fonction de la température électronique de la composition d'un plasma maxwellien d'azote a basse pression

The composition of a maxwellian nitrogen plasma has been determinated from the rate coefficients of the elementary processes which occur at low pressures. We assume the plasma to be optically thin ; excitations and three-body collisions are neglected. Fifteen processes are considered. The rate coefficients are computed with the generally admitted experimental cross-sections data. By means of a microreversibility formula, the radiative recombination cross-sections are deduced from the photoionization cross-sections. The computation of the rate coefficients has been performed for electron temperature values increasing from 0.2 to 10 eV. Evolution of the plasma ionization state is shown in this temperature range, initiale pressure value being 10-5 torr.La composition d'un plasma d'azote maxwellien est déterminée à partir des coefficients de réaction des processus élémentaires se produisant à basse pression. On suppose le plasma optiquement mince et on néglige les chocs triples et les excitations. Quinze processus sont inclus dans le bilan. Pour le calcul des coefficients de réaction, on utilise les données expérimentales de sections efficaces généralement admises. L'emploi d'une formule de microréversibilité permet de déduire les sections efficaces de recombinaison radiative de celles de photo-ionisation. Le calcul des coefficients de réaction a été effectué pour une température électronique allant de 0,2 à 10 eV. L'évolution de l'état d'ionisation du plasma est représenté dans cet intervalle de température pour une pression initiale de 10-5 torr