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Hirooka Y.,Japan National Institute for Fusion Science | Mazzitelli G.,ENEA | Mirnov S.V.,TRINITI | Ono M.,Princeton Plasma Physics Laboratory | And 2 more authors.
Nuclear Fusion | Year: 2010

Conference report of the 1st International Workshop on Lithium Applications to Boundary Control in Fusion Devices, held on January 18-20, 2010, is presented. The first talk of the workshop presented by H.Kugel of PPPL provided an overview on lithium applications to the boundary control in NSTX. Discussions also covered topic of ablation behavior of lithium in comparison with higher-Z materials under intense heat loads. Mazzitelli of ENEA presented an overview on the boundary controlled experiments in FTU using a capillary porous liquid lithium limiter, which is positioned a few centimeters off the true last closed flux surface determined by the main limiter. I. Murakami of NIFS reported on atomic and molecular reactions modeling for the Li H e system at electron temperatures relevant to the edge region of a confinement device, based on the experimental data taken in the LIGHT-1 facility.

Semenov S.,Keele University | Kellam J.,Carolinas Medical Center | Nair B.,TRINITI | Williams T.,Keele University | And 4 more authors.
Physics in Medicine and Biology | Year: 2011

Medical imaging has recently expanded into the dual- or multi-modality fusion of anatomical and functional imaging modalities. This significantly improves the diagnostic power while simultaneously increasing the cost of already expensive medical devices or investigations and decreasing their mobility. We are introducing a novel imaging concept of four-dimensional (4D) microwave tomographic (MWT) functional imaging: three dimensional (3D) in the spatial domain plus one dimensional (1D) in the time, functional dynamic domain. Instead of a fusion of images obtained by different imaging modalities, 4D MWT fuses absolute anatomical images with dynamic, differential images of the same imaging technology. The approach was successively validated in animal experiments with short-term arterial flow reduction and a simulated compartment syndrome in an initial simplified experimental setting using a dedicated MWT system. The presented fused images are not perfect as MWT is a novel imaging modality at its early stage of the development and ways of reading reconstructed MWT images need to be further studied and understood. However, the reconstructed fused images present clear evidence that microwave tomography is an emerging imaging modality with great potentials for functional imaging. © 2011 Institute of Physics and Engineering in Medicine.

Ono M.,Princeton Plasma Physics Laboratory | Bell M.G.,Princeton Plasma Physics Laboratory | Hirooka Y.,Japan National Institute for Fusion Science | Kaita R.,Princeton Plasma Physics Laboratory | And 7 more authors.
Nuclear Fusion | Year: 2012

The 2nd International Symposium on Lithium Applications for Fusion Devices (ISLA-2011) was held on 27-29 April 2011 at the Princeton Plasma Physics Laboratory (PPPL) with broad participation from the community working on aspects of lithium research for fusion energy development. This community is expanding rapidly in many areas including experiments in magnetic confinement devices and a variety of lithium test stands, theory and modeling and developing innovative approaches. Overall, 53 presentations were given representing 26 institutions from 10 countries. The latest experimental results from nine magnetic fusion devices were given in 24 presentations, from NSTX (PPPL, USA), LTX (PPPL, USA), FT-U (ENEA, Italy), T-11M (TRINITY, RF), T-10 (Kurchatov Institute, RF), TJ-II (CIEMAT, Spain), EAST (ASIPP, China), HT-7 (ASIPP, China), and RFX (Padova, Italy). Sessions were devoted to: I. Lithium in magnetic confinement experiments (facility overviews), II. Lithium in magnetic confinement experiments (topical issues), III. Special session on liquid lithium technology, IV. Lithium laboratory test stands, V. Lithium theory/modeling/comments, VI. Innovative lithium applications and VII. Panel discussion on lithium PFC viability in magnetic fusion reactors. There was notable participation from the fusion technology communities, including the IFE, IFMIF and TBM communities providing productive exchanges with the physics oriented magnetic confinement lithium research groups. It was agreed to continue future exchanges of ideas and data to help develop attractive liquid lithium solutions for very challenging magnetic fusion issues, such as development of a high heat flux steady-state divertor concept and acceptable plasma disruption mitigation techniques while improving plasma performance with lithium. The next workshop will be held at ENEA, Frascati, Italy in 2013. © 2012 IAEA, Vienna.

Digest of Technical Papers-IEEE International Pulsed Power Conference | Year: 2015

Generation of series of repetitive shots by a railgun is associated with solution of some basic and applied problems. The very first basic one is a high-density energy source with long-Time energy storage and fast-Time release of the stored energy to the load. Another ones are associated with the pulsed generator operating either without additional external power sources or, at least, with the minimum number of ones, and the time varying external magnetic field which is inherent to all railguns. All the applied problems are associated with the type of the load. The revolver railgun design is proposed to solve these problems. This design has a number of advantages over the conventional railgun design. One can see for example that the railgun discharge current decreases proportionally to number of armature in the revolver railgun while the applied voltage increases, which is subject of the equality of both mass and velocity of armature. This allows one to optimize the parameters of the inductive storage and its opening switch. The revolver railgun design also increases its own spatial stability during series of repetitive shots of armatures, as well as stability of radial component of the railgun discharge currents and stability of launched armatures, which is associated with non uniformity of the radial magnetic field. Some specific space applications of a revolver railgun combined with a space-propulsion ion engine is discussed in the Appendix. © 2015 IEEE.

Leonov S.B.,Russian Academy of Sciences | Kochetov I.V.,TRINITI | Napartovich A.P.,TRINITI | Sabel'Nikov V.A.,ONERA | Yarantsev D.A.,Russian Academy of Sciences
IEEE Transactions on Plasma Science | Year: 2011

The results of laboratory-scale experiments on plasma-induced hydrogen and ethylene ignition and flameholding by means of near-surface electrical discharge are presented. The ignition and flameholding were demonstrated for direct fuel injection into the supersonic air. A two-zone model of plasma-induced ignition is proposed to explain the experimental data. Numerical simulations were performed to confirm the two-zone model of plasma-assisted ignition. © 2010 IEEE.

Mirnov S.V.,TRINITI | Lazarev V.B.,TRINITI
Journal of Nuclear Materials | Year: 2011

The renewable plasma facing components (PFCs) of steady state tokamak-reactor can be created in framework of Lithium emitter-collector concept, which suggests Li-loop development close the Li-PFC and plasma periphery. It should ensure: Li-emission from PFC into the plasma, plasma periphery cooling by non-coronal Li radiation, Li ions collection before their loss on the wall and Li return into emitter. The subjects of the last T-11 M investigations were the Lithium collection by limiters and Lithium removal from the wall during tokamak conditioning. The Lithium behavior was studied with witness samples and mobile graphite probe. It was shown that Li-deposit on the sides of rail Li-limiter (collector) is proportional to the Li-emission from the Li-limiter (emitter). Lithium deposit on the ion-drift side of Li-limiter is up to 2-3 times more than on the electron-side. The efficiency of Li-collection by T-11 M limiters can be 60 ± 20% of total Lithium emission from Li-limiter during plasma discharges. © 2010 Elsevier B.V. All rights reserved.

Proceedings - International Symposium on Discharges and Electrical Insulation in Vacuum, ISDEIV | Year: 2010

The article proposes a fundamentally new approach to the problem of breaking high currents of 100kA or more. The vacuum discharger and the vacuum interrupter differ significantly in the rate of electric strength recovery, size of electrode erosion and etc. This is due to the difference in the type of the discharge. In the report considered we suggested that to align these values the current I should be closed through the spark gap prior to moving the electrodes of the vacuum interrupter; at this its value is above the initial by ΔI (ΔI-current, ΔI/I0 ∼5÷10•10 -2). The excess ΔI-current flows through the vacuum interrupter, but in the reverse direction. In the course of moving the electrodes apart, the ΔI-current falls to zero with a time constant t=L/R, where L and R are the inductance of the contour (vacuum interrupter- spark gap) and resistance of the discharge of the discharge gap, respectively. This makes it possible to quickly recover the electric strength of the gap between the contacts, substantially reduce the electrode erosion and significantly decrease the breaking voltage of the ΔI-current. At the final stage the discharge of the countercurrent battery recovers the vacuum strength of the discharge gap. Such method of current breaking allows for the effective interruption of direct currents of high power. The method was developed in terms of the combination current breaker (vacuum interrupter and plasma opening switch). Spark gap is replaced to mobile plasma gap in design of combination opening switch. The article considers -construction of switch; -described of action steps; -energy characteristics of circuit, in the context to progress of conception pulsed generators based on inductive storage. ©2010 IEEE.

Semenov S.,Keele University | Kellam J.,Carolinas Medical Center | Sizov Y.,TRINITI | Nazarov A.,INTEGRIT | And 5 more authors.
Physics in Medicine and Biology | Year: 2011

Microwave tomography (MWT) is a novel imaging modality which might be applicable for non-invasive assessment of functional and pathological conditions of biological tissues. Imaging of the soft tissue of extremities is one of its potential applications. The feasibility of this technology for such applications was demonstrated earlier. This is the first of two companion papers focused on an application of MWT for imaging of the extremity's soft tissues. The goal of this study is to assess the technical performance of the developed 2D MWT system dedicated for imaging of functional and pathological conditions of the extremity's soft tissues. Specifically, the system's performance was tested by its ability to detect signals associated with physiological activity and soft tissue interventions (circulatory related changes, blood flow reduction and a simulated compartmental syndrome) - the so-called physiological signatures. The developed 2D MWT system dedicated to the imaging of animal extremities demonstrates good technical performance allowing for stable and predictable data acquisition with reasonable agreement between the experimentally measured electromagnetic (EM) field and the simulated EM field within a measurement domain. Using the system, we were able to obtain physiological signatures associated with systolic versus diastolic phases of circulation in an animal extremity, reperfusion versus occlusion phases of the blood supply to the animal's extremity and a compartment syndrome. The imaging results are presented and discussed in the second companion paper. © 2011 Institute of Physics and Engineering in Medicine.

Proceedings of the 2014 IEEE International Power Modulator and High Voltage Conference, IPMHVC 2014 | Year: 2014

The process of generating series pulses and pulse trains based on inductive storage is associated with solving several common problems, such as attaining high resources of opening switches, adapting separate components of opening switch construction, and adapting load construction to solve a required task while maintaining pulse parameters. This paper proposes to consider the main parts of generation technology in providing pulse series and pulse train. © 2014 IEEE.

Digest of Technical Papers-IEEE International Pulsed Power Conference | Year: 2015

The technical solutions are proposed for the pulse generator based on a transformer-like inductive storage of energy (TIS). This work describes construction and components of a single turn TIS, as well as some basic operation principles of a semi-conductor switch used in combination with the TIS the fact that there is no need in opening of the primary winding permitting one to consider a construction capable to generate high power pulses in the repetitive pulse mode is among the advantages of the proposed technical solution the next important aspect that should be noted here is the coefficient of power gain, which is ∼104 and more the poloidal current of the energy storage is among the unsolved problems. This current requires additional components that need to be introduced into the pulse generator construction with the goal of maximum possible compensation of the poloidal current. One of possible ways to solve the above problem is to use an inductively-coupled duel transformer storage the solution allows one to solve the following two problems simultaneously: compensation of the poloidal current and increase of the load current. © 2015 IEEE.

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