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Safronova, Alla

Publications and source records attributed to Safronova, Alla.

5 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2017

Plasma: at the frontier of scientific discovery

In February 2015, the Department of Energy, Office of Science, Fusion Energy Sciences (FES)” announced the formation of four technical workshops “to seek community engagement and input for future program planning activities.” Three of these workshops focused on the science and technical challenges we must address to meet the emerging needs of ITER and to allow exploration of fusion burning plasma physics in the laboratory. This report represents the work of the fourth workshop, which focused on the broader scientific opportunities at the frontiers of plasma science. The primary charge to the Panel authoring this report was “to ‘identify’ compelling scientific challenges at the frontiers of plasma physics” and “to ‘identify’ research tools and capabilities to address these challenges in the next decade.” This report aims to inform the newly constituted FES Program in Frontiers of Plasma Science on science opportunities and strategy moving forward. This program was created in FY2015 by combining topics from general plasma science, high energy density laboratory plasmas, and exploratory magnetized plasma into a single program area. The Executive Summary, chapter introductions and sidebars to the chapter are intended to provide more general overviews of the findings of the panel. The chapters provide more details following these themes.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2016

Conference Grant Proposal for ICOPS 2016

ICOPS (International Conference on Plasma Science) is an internationally renowned, well-attended annual conference that involves topics of direct interest to the Office of Fusion Energy Sciences of Department of Energy. In particular, ICOPS 2016 emphasized both the traditional areas of plasma science and the new areas of growth that include but are not limited to Fusion (Inertial, Magnetic and Alternate Concepts), Particle Acceleration with Laser and Beams, High Energy Density Matter, Laser Produced Plasma, Fast Z-pinches, Computational Plasma Physics, Plasma Diagnostics, and such frontiers as studying Warm Dense Matter using the X-ray free electron lasers. The travel support of the students at ICOPS comes usually from sponsor organizations. Increasing the participation of outstanding students at ICOPS 2016 who are the first authors of the abstracts and are selected to receive the travel support based on the scientific merit of the submitted abstracts is crucial for the creation of the new generation of the plasma physicists.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2014

Theoretical Study of Radiation from a Broad Range of Impurity Ions for Magnetic Fusion Diagnostics

Spectroscopy of radiation emitted by impurities plays an important role in the study of magnetically confined fusion plasmas. The measurements of these impurities are crucial for the control of the general machine conditions, for the monitoring of the impurity levels, and for the detection of various possible fault conditions. Low-Z impurities, typically present in concentrations of 1%, are lithium, beryllium, boron, carbon, and oxygen. Some of the common medium-Z impurities are metals such as iron, nickel, and copper, and high-Z impurities, such as tungsten, are present in smaller concentrations of 0.1% or less. Despite the relatively small concentration numbers, the aforementioned impurities might make a substantial contribution to radiated power, and also influence both plasma conditions and instruments. A detailed theoretical study of line radiation from impurities that covers a very broad spectral range from less than 1 Å to more than 1000 Å has been accomplished and the results were applied to the LLNL Electron Beam Ion Trap (EBIT) and the Sustained Spheromak Physics Experiment (SSPX) and to the National Spherical Torus Experiment (NSTX) at Princeton. Though low- and medium-Z impurities were also studied, the main emphasis was made on the comprehensive theoretical study of radiation from tungsten using different state-of-the-art atomic structure codes such as Relativistic Many-Body Perturbation Theory (RMBPT). The important component of this research was a comparison of the results from the RMBPT code with other codes such as the Multiconfigurational Hartree–Fock developed by Cowan (COWAN code) and the Multiconfiguration Relativistic Hebrew University Lawrence Atomic Code (HULLAC code), and estimation of accuracy of calculations. We also have studied dielectronic recombination, an important recombination process for fusion plasma, for variety of highly and low charged tungsten ions using COWAN and HULLAC codes. Accurate DR rate coefficients are needed for describing the ionization balance of plasmas, which in turn determines the lines contributing to the spectral emission and the radiative power loss. In particular, we have calculated relativistic atomic data and corresponding dielectronic satellite spectra of highly ionized W ions, such as, for example, Li-like W (with the shortest wavelength of x-ray radiation of about 0.2 Å) that might exist in ITER core plasmas at very high temperatures of 30-40 keV. In addition, we have completed relativistic calculations of low ionized W ions from Lu-like (W3+) to Er-like (W6+) and for Sm-like(W12+) and Pm-like (W13+) that cover a spectral range from few hundred to thousand Å and are more relevant to the edge plasma diagnostics in tokamak.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗