Operational characteristics of the superconducting high flux plasma generator Magnum-PSI

\u3cp\u3eThe interaction of intense plasma impacting on the wall of a fusion reactor is an area of high and increasing importance in the development of electricity production from nuclear fusion. In the Magnum-PSI linear device, an axial magnetic field confines a high density, low temperature plasma produced by a wall stabilized DC cascaded arc into an intense magnetized plasma beam directed onto a target. The experiment has shown its capability to reach conditions that enable fundamental studies of plasma-surface interactions in the regime relevant for fusion reactors such as ITER: 10\u3csup\u3e23\u3c/sup\u3e–10\u3csup\u3e25\u3c/sup\u3e m\u3csup\u3e−2\u3c/sup\u3es\u3csup\u3e−1\u3c/sup\u3e hydrogen plasma flux densities at 1–5 eV for tens of seconds by using conventional electromagnets. Recently the machine was upgraded with a superconducting magnet, enabling steady-state magnetic fields up to 2.5 T, expanding the operational space to high fluence capabilities for the first time. Also the diagnostic suite has been expanded by a new 4-channel resistive bolometer array and ion beam analysis techniques for surface analysis after plasma exposure of the target. A novel collective Thomson scattering system has been developed and will be implemented on Magnum-PSI. In this contribution, the current status, capabilities and performance of Magnum-PSI are presented.\u3c/p\u3

High-fluence and high-flux performance characteristics of the superconducting Magnum-PSI linear plasma facility

\u3cp\u3e The Magnum-PSI facility is unique in its ability to produce and even exceed the heat and particle fluxes expected in the divertor of a fusion reactor, combined with good access to the plasma-material interaction region for diagnostics and relatively easy sample manipulation. In addition, it is possible to study the effects of transient heat loads on a plasma-facing surface, similar to those expected during so called Edge Localized Modes. By virtue of a newly installed superconducting magnet, Magnum-PSI can now maintain these conditions for hours on end for truly long term tests of candidate plasma facing materials. The electron density and temperature in the plasma beam center as a function of different magnetic fields up to 1.6 T, gas flow and source current are determined: particle fluxes greater than 10 \u3csup\u3e25\u3c/sup\u3e m \u3csup\u3e−2\u3c/sup\u3e s \u3csup\u3e−1\u3c/sup\u3e and heat fluxes of up to 50 MW m \u3csup\u3e−2\u3c/sup\u3e are obtained. Linear regression and artificial neural network analysis have been used to gain insight in the general behavior of plasma conditions as a function of these machine settings. The plasma conditions during transient plasma heat loading have also been determined. These capabilities are now being exploited to reach fluence of up to 10 \u3csup\u3e30\u3c/sup\u3e particles m \u3csup\u3e−2\u3c/sup\u3e at ITER-relevant conditions, equivalent to a significant fraction of the divertor service lifetime for the first time. \u3c/p\u3

Operational characteristics of the high flux plasma generator magnum-PSI

\u3cp\u3eIn Magnum-PSI (MAgnetized plasma Generator and NUMerical modeling for Plasma Surface Interactions), the high density, low temperature plasma of a wall stabilized dc cascaded arc is confined to a magnetized plasma beam by a quasi-steady state axial magnetic field up to 1.3 T. It aims at conditions that enable fundamental studies of plasma-surface interactions in the regime relevant for fusion reactors such as ITER: 10\u3csup\u3e23\u3c/sup\u3e-10\u3csup\u3e25\u3c/sup\u3e m \u3csup\u3e-2\u3c/sup\u3e s\u3csup\u3e-1\u3c/sup\u3e hydrogen plasma flux densities at 1-5 eV. To study the effects of transient heat loads on a plasma-facing surface, a high power pulsed magnetized arc discharge has been developed. Additionally, the target surface can be transiently heated with a pulsed laser system during plasma exposure. In this contribution, the current status, capabilities and performance of Magnum-PSI are presented.\u3c/p\u3

Chemical erosion of different carbon composites under ITER-relevant plasma conditions

\u3cp\u3eWe have studied the chemical erosion of different carbon composites in Pilot-PSI at ITER-relevant hydrogen plasma fluxes (∼10\u3csup\u3e24\u3c/sup\u3e m \u3csup\u3e-2\u3c/sup\u3e s\u3csup\u3e-1\u3c/sup\u3e) and low electron temperatures (T\u3csub\u3ee\u3c/sub\u3e∼1 eV). Optical emission spectroscopy on the CH A-X band was used to characterize the chemical sputtering. Fine grain graphite (R 6650, SGL Carbon Group), ITER-reference carbon fiber composite material (SNECMA NB31 and NB41; Dunlop 3D), nano- and micro-crystalline diamond coatings on molybdenum and SiC (Silit® SKD Reaction-Bonded, Saint-Gobain Ceramics) were compared. The chemical sputtering was similar for the different composites under comparable plasma conditions, except for SiC, which produced a ten times lower rate. The CH emission was constant at electron temperatures T\u3csub\u3ee\u3c/sub\u3e>1 eV and ion fluxes ranging between 10\u3csup\u3e23\u3c/sup\u3e and 10\u3csup\u3e24\u3c/sup\u3e m\u3csup\u3e- 2\u3c/sup\u3e s\u3csup\u3e-1\u3c/sup\u3e, but decreased at lower temperatures. This decrease is possibly due to changes in the excitation of CH and not due to a change in the chemical erosion rate.\u3c/p\u3

The role of religious leaders in promoting acceptance of vaccination within a minority group: a qualitative study

Contains fulltext : 117840.pdf (publisher's version ) (Open Access)BACKGROUND: Although childhood vaccination programs have been very successful, vaccination coverage in minority groups may be considerably lower than in the general population. In order to increase vaccination coverage in such minority groups involvement of faith-based organizations and religious leaders has been advocated. We assessed the role of religious leaders in promoting acceptance or refusal of vaccination within an orthodox Protestant minority group with low vaccination coverage in The Netherlands. METHODS: Semi-structured interviews were conducted with orthodox Protestant religious leaders from various denominations, who were selected via purposeful sampling. Transcripts of the interviews were thematically analyzed, and emerging concepts were assessed for consistency using the constant comparative method from grounded theory. RESULTS: Data saturation was reached after 12 interviews. Three subgroups of religious leaders stood out: those who fully accepted vaccination and did not address the subject, those who had religious objections to vaccination but focused on a deliberate choice, and those who had religious objections to vaccination and preached against vaccination. The various approaches of the religious leaders seemed to be determined by the acceptance of vaccination in their congregation as well as by their personal point of view. All religious leaders emphasized the importance of voluntary vaccination programs and religious exemptions from vaccination requirements. In case of an epidemic of a vaccine preventable disease, they would appreciate a dialogue with the authorities. However, they were not willing to promote vaccination on behalf of authorities. CONCLUSION: Religious leaders' attitudes towards vaccination vary from full acceptance to clear refusal. According to orthodox Protestant church order, local congregation members appoint their religious leaders themselves. Obviously they choose leaders whose views are compatible with the views of the congregation members. Moreover, the positions of orthodox Protestant religious leaders on vaccination will not change easily, as their objections to vaccination are rooted in religious doctrine and they owe their authority to their interpretation and application of this doctrine. Although the dialogue with religious leaders that is pursued by the Dutch government may be helpful in controlling epidemics by other means than vaccination, it is unlikely to increase vaccination coverage

OVERVIEW OF CORE DIAGNOSTICS FOR TEXTOR

The diagnostic system of TEXTOR comprises about 50 individual diagnostic devices. Since the start of the Trilateral Euregio Cluster collaboration, part of the emphasis in the experimental program has shifted toward the study of physics processes in the plasma core. To aid these studies several new and advanced core diagnostics have been implemented, whereas a number of other core diagnostics have been upgraded to higher resolution, more channels, and better accuracy. In this paper a brief overview is given of the present set of plasma core diagnostics at TEXTOR.X1114sciescopu

A public relations identity for the 2010s

New voices are being heard and new questions are being asked within the field of public relations. However, in its present multifaceted state, public relations research is still struggling with recurring questions regarding academic and practical contributions. This position article presents some common starting points for a public relations identity for the 2010s aiming to preserve both consistency and multiplicity. We argue that public relations should be studied as a social activity in its own right and that it must be understood in relation to its societal context. Furthermore, we point to some concepts (trust, legitimacy, understanding and reflection) that are crucial to understanding public relations practice. We also argue that issues of power, behavior, and language have to be dealt with if public relations is to be taken seriously as an academic field. Building on these ideas we make some suggestions for empirical research. Finally, we propose, on a philosophical level, to develop a critical realist framework in order to study public relations scientifically