Fundamentals of Plasma-Material Interactions in Magnetic Fusion Devices

The interaction of plasmas and materials has a long history in the modification of condensed matter. Plasma-material interaction (PMI) can govern how low-temperature and high-temperature plasmas interact and modify materials surfaces. In magnetic fusion devices, PMI can also influence the operation of the fusion device. For example, incident energetic charged particle on fusion wall material surfaces can release target atoms via sputtering and can implant fuel particles in the lattice. Implanted energetic particles can mix fuel and influence recycling of fuel back to the plasma. Sputtered target atoms can become ionized in the magnetic sheath and re-deposit at the wall surface. The magnetic sheath will influence the energy and angular distribution of incident energetic particles and influence the implantation and release of fusion fuel

Surface Plasma Arc by Radio-Frequency Control Study (SPARCS)

This paper is to summarize the work carried out between April 2012 and April 2013 for development of an experimental device to simulate interactions of o#11;-normal detrimental events in a tokamak and ICRF antenna. The work was mainly focused on development of a pulsed plasma source using theta pinch and coaxial plasma gun. This device, once completed, will have a possible application as a test stand for high voltage breakdown of an ICRF antenna in extreme events in a tokamak such as edge-localized modes or disruption. Currently, DEVeX does not produce plasma with high temperature enough to requirement for an ELM simulator. However, theta pinch is a good way to produce high temperature ions. The unique characteristic of plasma heating by a theta pinch is advantageous for an ELM simulator due to its effective ion heating. The objective of the proposed work, therefore, is to build a test facility using the existing theta pinch facility in addition to a coaxial plasma gun. It is expected to produce a similar pulsed-plasma heat load to the extreme events in tokamaks and to be applied for studying interactions of hot plasma and ICRF antennas

Photo-Optical Instrumentation Engineers (SPIE)

Abstract. A theoretical model for describing the propagation and scattering of energetic species in an extreme ultraviolet (EUV) light lithography source is presented. An EUV light emitting XTREME XTS 13-35 Z-pinch plasma source is modeled with a focus on the effect of chamber pressure and buffer gas mass on energetic ion and neutral debris transport. The interactions of the energetic debris species, which is generated by the EUV light emitting plasma, with the buffer gas and chamber walls are considered as scattering events in the model, and the trajectories of the individual atomic species involved are traced using a Monte Carlo algorithm. This study aims to establish the means by which debris is transported to the intermediate focus with the intent to verify the various mitigation techniques currently employed to increase EUV lithography efficiency. The modeling is compared with an experimental investigation

Does physical activity change predict functional recovery in low back pain? Protocol for a prospective cohort study

Background: Activity advice and prescription are commonly used in the management of low back pain (LBP). Although there is evidence for advising patients with LBP to remain active, facilitating both recovery and return to work, to date no research has assessed whether objective measurements of free living physical activity (PA) can predict outcome, recovery and course of LBP. Methods: An observational longitudinal study will investigate PA levels in a cohort of community-dwelling working age adults with acute and sub-acute LBP. Each participant's PA level, functional status, mood, fear avoidance behaviours, and levels of pain, psychological distress and occupational activity will be measured on three occasions during for 1 week periods at baseline, 3 months, and 1 year. Physical activity levels will be measured by self report, RT3 triaxial accelerometer, and activity recall questionnaires. The primary outcome measure of functional recovery will be the Roland Morris Disability Questionnaire (RMDQ). Free living PA levels and changes in functional status will be quantified in order to look at predictive relationships between levels and changes in free living PA and functional recovery in a LBP population. Discussion: This research will investigate levels and changes in activity levels of an acute LBP cohort and the predictive relationship to LBP recovery. The results will assess whether occupational, psychological and behavioural factors affect the relationship between free living PA and LBP recovery. Results from this research will help to determine the strength of evidence supporting international guidelines that recommend restoration of normal activity in managing LBP. Trial registration. [Clinical Trial Registration Number, ACTRN12609000282280]. © 2009 Hendrick et al; licensee BioMed Central Ltd

Large-scale unit commitment under uncertainty: an updated literature survey

The Unit Commitment problem in energy management aims at finding the optimal production schedule of a set of generation units, while meeting various system-wide constraints. It has always been a large-scale, non-convex, difficult problem, especially in view of the fact that, due to operational requirements, it has to be solved in an unreasonably small time for its size. Recently, growing renewable energy shares have strongly increased the level of uncertainty in the system, making the (ideal) Unit Commitment model a large-scale, non-convex and uncertain (stochastic, robust, chance-constrained) program. We provide a survey of the literature on methods for the Uncertain Unit Commitment problem, in all its variants. We start with a review of the main contributions on solution methods for the deterministic versions of the problem, focussing on those based on mathematical programming techniques that are more relevant for the uncertain versions of the problem. We then present and categorize the approaches to the latter, while providing entry points to the relevant literature on optimization under uncertainty. This is an updated version of the paper "Large-scale Unit Commitment under uncertainty: a literature survey" that appeared in 4OR 13(2), 115--171 (2015); this version has over 170 more citations, most of which appeared in the last three years, proving how fast the literature on uncertain Unit Commitment evolves, and therefore the interest in this subject

Neutral atom, molecule and edge-plasma modeling for ITER. Final progress report for period January 15, 1995 - February 14, 1999

Over the past three years, eleven refereed journal publications [1-11] have resulted in part from this grant. These can be arranged into three categories: (1) Erosion/redeposition calculations of current machines and proposed designs, (2) Analysis of proposed long-pulse or burning plasma operating regimes, and (3) Analysis of neutral behavior in current experiments. Each paper is listed below along with a very short synopsis of the importance or significance of the work in each category. Since refereed work in significant journals is the purest distillation of written results, the entire papers are included after these brief descriptions

Final report for ER54440, ''Measurement and modeling of low energy (910 to 1000 eV) sputtering and reflection''

This report is a compilation of the three annual progress reports. All detail can be found in the refereed publications enumerated within