The Experts below are selected from a list of 309264 Experts worldwide ranked by ideXlab platform
Mirko Salewski - One of the best experts on this subject based on the ideXlab platform.
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the prospect for fuel ion ratio measurements in iter by collective thomson scattering
Nuclear Fusion, 2012Co-Authors: M. Stejner, Søren Bang Korsholm, Henrik Bindslev, Stefan Kragh Nielsen, Mirko Salewski, V Furtula, Frank Leipold, Poul Michelsen, F Meo, D MoseevAbstract:We show that collective Thomson scattering (CTS) holds the potential to become a new diagnostic principle for measurements of the fuel ion ratio, nT/nD, in ITER. Fuel ion ratio measurements will be important for Plasma Control and machine protection in ITER. Measurements of ion cyclotron structures in CTS spectra have been suggested as the basis for a new fuel ion ratio diagnostic which would be well suited for reactor environments and capable of providing spatially resolved measurements in the Plasma core. Such measurements were demonstrated in recent experiments in the TEXTOR tokamak. Here we conduct a sensitivity study to investigate the potential measurement accuracy of a CTS fuel ion ratio diagnostic on ITER. The study identifies regions of parameter space in which CTS can be expected to provide useful information on Plasma composition, and we find that a CTS fuel ion ratio diagnostic could meet the ITER measurement requirements for a standard ELMy H-mode discharge.
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Principles of fuel ion ratio measurements in fusion Plasmas by collective Thomson scattering
Plasma Physics and Controlled Fusion, 2011Co-Authors: M. Stejner, Søren Bang Korsholm, Henrik Bindslev, Stefan Kragh Nielsen, Mirko SalewskiAbstract:For certain scattering geometries collective Thomson scattering (CTS) measurements are sensitive to the composition of magnetically confined fusion Plasmas. CTS therefore holds the potential to become a new diagnostic for measurements of the fuel ion ratio?i.e. the tritium to deuterium density ratio. Measurements of the fuel ion ratio will be important for Plasma Control and machine protection in future experiments with burning fusion Plasmas. Here we examine the theoretical basis for fuel ion ratio measurements by CTS. We show that the sensitivity to Plasma composition is enhanced by the signatures of ion cyclotron motion and ion Bernstein waves which appear for scattering geometries with resolved wave vectors near perpendicular to the magnetic field. We investigate the origin and properties of these features in CTS spectra and give estimates of their relative importance for fuel ion ratio measurements.
M. Stejner - One of the best experts on this subject based on the ideXlab platform.
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the prospect for fuel ion ratio measurements in iter by collective thomson scattering
Nuclear Fusion, 2012Co-Authors: M. Stejner, Søren Bang Korsholm, Henrik Bindslev, Stefan Kragh Nielsen, Mirko Salewski, V Furtula, Frank Leipold, Poul Michelsen, F Meo, D MoseevAbstract:We show that collective Thomson scattering (CTS) holds the potential to become a new diagnostic principle for measurements of the fuel ion ratio, nT/nD, in ITER. Fuel ion ratio measurements will be important for Plasma Control and machine protection in ITER. Measurements of ion cyclotron structures in CTS spectra have been suggested as the basis for a new fuel ion ratio diagnostic which would be well suited for reactor environments and capable of providing spatially resolved measurements in the Plasma core. Such measurements were demonstrated in recent experiments in the TEXTOR tokamak. Here we conduct a sensitivity study to investigate the potential measurement accuracy of a CTS fuel ion ratio diagnostic on ITER. The study identifies regions of parameter space in which CTS can be expected to provide useful information on Plasma composition, and we find that a CTS fuel ion ratio diagnostic could meet the ITER measurement requirements for a standard ELMy H-mode discharge.
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Principles of fuel ion ratio measurements in fusion Plasmas by collective Thomson scattering
Plasma Physics and Controlled Fusion, 2011Co-Authors: M. Stejner, Søren Bang Korsholm, Henrik Bindslev, Stefan Kragh Nielsen, Mirko SalewskiAbstract:For certain scattering geometries collective Thomson scattering (CTS) measurements are sensitive to the composition of magnetically confined fusion Plasmas. CTS therefore holds the potential to become a new diagnostic for measurements of the fuel ion ratio?i.e. the tritium to deuterium density ratio. Measurements of the fuel ion ratio will be important for Plasma Control and machine protection in future experiments with burning fusion Plasmas. Here we examine the theoretical basis for fuel ion ratio measurements by CTS. We show that the sensitivity to Plasma composition is enhanced by the signatures of ion cyclotron motion and ion Bernstein waves which appear for scattering geometries with resolved wave vectors near perpendicular to the magnetic field. We investigate the origin and properties of these features in CTS spectra and give estimates of their relative importance for fuel ion ratio measurements.
R. D. Johnson - One of the best experts on this subject based on the ideXlab platform.
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the web based user interface for east Plasma Control system
Fusion Engineering and Design, 2014Co-Authors: Ruili Zhang, R. D. Johnson, Bingjia Xiao, Q P Yuan, Fei Yang, Yang Zhang, Ben G. PenaflorAbstract:Abstract The Plasma Control system (PCS) plays a vital role at EAST for fusion science experiments. Its software application consists of two main parts: an IDL graphical user interface for setting a large number of Plasma parameters to specify each discharge, several programs for performing the real-time feedback Control and managing the whole Control system. The PCS user interface can be used from any X11 Windows client with privileged access to the PCS computer system. However, remote access to the PCS system via the IDL user interface becomes an extreme inconvenience due to the high network latency to draw or operate the interfaces. In order to realize lower latency for remote access to the PCS system, a web-based system has been developed for EAST recently. The setup data are retrieved from the PCS system and client-side JavaScript draws the interfaces into the user's browser. The user settings are also sent back to the PCS system for Controlling discharges. These technologies allow the web-based user interface to be viewed by authorized users with a web browser and have it communicate with PCS server processes directly. It works together with the IDL interface and provides a new way to aid remote participation.
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toroidal current profile Control during low confinement mode Plasma discharges in diii d via first principles driven model based robust Control synthesis
Nuclear Fusion, 2012Co-Authors: Justin Barton, Tim C Luce, Mark D. Boyer, David A. Humphreys, Michael L. Walker, Ben G. Penaflor, John R. Ferron, Eugenio Schuster, R. D. JohnsonAbstract:In order for ITER to be capable of operating in advanced tokamak operating regimes, characterized by a high fusion gain, good Plasma confinement, magnetohydrodynamic stability and a non-inductively driven Plasma current, for extended periods of time, several challenging Plasma Control problems still need to be solved. Setting up a suitable toroidal current density profile in the tokamak is key for one possible advanced operating scenario characterized by non-inductive sustainment of the Plasma current. At the DIII-D tokamak, the goal is to create the desired current profile during the ramp-up and early flat-top phases of the Plasma discharge and then actively maintain this target profile for the remainder of the discharge. The evolution in time of the toroidal current profile in tokamaks is related to the evolution of the poloidal magnetic flux profile, which is modelled in normalized cylindrical coordinates using a first-principles, nonlinear, dynamic partial differential equation (PDE) referred to as the magnetic diffusion equation. The magnetic diffusion equation is combined with empirical correlations developed from physical observations and experimental data from DIII-D for the electron temperature, the Plasma resistivity and the non-inductive current drive to develop a simplified, Control-oriented, nonlinear, dynamic PDE model of the poloidal flux profile evolution valid for low confinement mode discharges. In this work, we synthesize a robust feedback Controller to reject disturbances and track a desired reference trajectory of the poloidal magnetic flux gradient profile by employing the Control-oriented model of the system. A singular value decomposition of the static gain matrix of the plant model is utilized to identify the most relevant Control channels and is combined with the dynamic response of system around a given operating trajectory to design the feedback Controller. A general framework for real-time feedforward + feedback Control of magnetic and kinetic Plasma profiles was implemented in the DIII-D Plasma Control System and was used to demonstrate the ability of the feedback Controller to Control the toroidal current profile evolution in the DIII-D tokamak. These experiments constitute the first time ever a first-principles-driven, model-based, closed-loop magnetic profile Controller was successfully implemented and tested in a tokamak device.
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Plasma Control system for day one operation of kstar tokamak
Symposium On Fusion Technology, 2009Co-Authors: S H Hahn, M.l. Walker, Ben G. Penaflor, D.a. Piglowski, R. D. Johnson, K H Kim, H S Ahn, Jaehoon Choi, Dongkeun Lee, Jayhyun KimAbstract:Abstract A complete Plasma Control system (PCS) has been developed for KSTAR’s first Plasma campaign as a collaborative project with the DIII-D team. The KSTAR real time Plasma Control system is based on a conceptual design by Jhang and Choi [Hogun Jhang, I.S. Choi, Fusion Engineering and Design 73 (2005) 35–49] and consists of a fast real-time computer/communication cluster and software derived from the GA-PCS [Penaflor, B.G., et.al., Fusion Engineering and Design, 83 (2) (2008) 176]. The system has been used for simulation testing, poloidal field (PF) coil power supply commissioning and first Plasma Control. The seven sets of up-down symmetric, superconducting PF coil/power supply systems have been successfully tested. Reflective memory (RFM) is utilized as the primary actuator/PCS real-time communication layer and PCS synchronization with KSTAR timing system and slower Control devices is achieved through an EPICS implementation. Consistent feedback loop times of 100 microseconds has been achieved during PF coil power supply testing and first Plasma commissioning. Here we present the “Day-One” Plasma Control system in its final form for the first Plasma experimental campaign of KSTAR and describe how the system has been utilized during magnet commissioning and Plasma startup experiments.
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east Plasma Control system
Fusion Engineering and Design, 2008Co-Authors: B J Xiao, D A Pigrowski, M.l. Walker, J.a. Leuer, D. A. Humphreys, A.w. Hyatt, Ben G. Penaflor, R. D. Johnson, D. Mueller, A.s. WelanderAbstract:Abstract Experimental advanced superconducting tokamak (EAST), the first tokomak with ITER-like fully superconductive poloidal and toroidal coils, successfully completed its engineering commission in March 2006; had its first Plasma in September 2006 [B.N. Wan, et al., The first Plasma of EAST, in: 21st IAEA Fusion Energy Conference, Chengdu, China, 16–21 October, 2007. [1] ] and further generated diverted Plasma in January 2007. The Plasma Control system was adapted from DIII-D Plasma Control system architecture and jointly developed by the DIII-D and EAST Plasma Control team. After briefly outlining the hardware and software architecture of the EAST Plasma Control system, this paper summarizes the Plasma Control results in the first Plasma and first diverted Plasma campaigns.
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worldwide collaborative efforts in Plasma Control software development
Fusion Engineering and Design, 2008Co-Authors: Ben G. Penaflor, B J Xiao, M.l. Walker, J.a. Leuer, D. A. Humphreys, D.a. Piglowski, R. D. Johnson, J R Ferron, S H Hahn, D A GatesAbstract:This presentation will describe the DIII-D collaborations with various tokamak experiments throughout the world which have adapted custom versions of the DIII-D Plasma Control system (PCS) software for their own use. Originally developed by General Atomics for use on the DIII-D tokamak, the PCS has been successfully installed and used for the NSTX experiment in Princeton, the MAST experiment in Culham UK, the EAST experiment in China, and the Pegasus experiment in the University of Wisconsin. In addition to these sites, a version of the PCS is currently being developed for use by the KSTAR tokamak in Korea. A well-defined and robust PCS software infrastructure has been developed to provide a common foundation for implementing the real-time data acquisition and feedback Control codes. The PCS infrastructure provides a flexible framework that has allowed the PCS to be easily adapted to fulfill the unique needs of each site. The software has also demonstrated great flexibility in allowing for different computing, data acquisition and real-time networking hardware to be used. A description of the current PCS software architecture will be given along with experiences in developing and supporting the various PCS installations throughout the world.
G Ambrosino - One of the best experts on this subject based on the ideXlab platform.
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gpu optimized fast Plasma equilibrium reconstruction in fine grids for real time Control and data analysis
Nuclear Fusion, 2020Co-Authors: Yu Huang, Bingjia Xiao, G Ambrosino, Q P Yuan, M Mattei, Z P Luo, A Pironti, L L Lao, A Mele, Y M WangAbstract:P-EFIT, a GPU parallel equilibrium reconstruction code, is based on the EFIT framework, but built with the CUDA™ (Compute Unified Device Architecture) to take advantage of massively parallel Graphical Processing Unit (GPU) cores to significantly accelerate the computation. With the parallelized Grad-Shafranov solver and middle-scale matrix calculation modules, P-EFIT can accurately reproduce the EFIT reconstruction algorithms at a fraction of the EFIT computational time. Integrated into EAST Plasma Control system, P-EFIT not only provides Control signal results but also enhances EAST Plasma Control capacity with unique designed function modules. Using the synthetic magnetic diagnostic signals from ITER Plasma equilibria obtained by the CREATE-L and CREATE-NL codes in standalone and streaming mode, P-EFIT has good enough accuracy and time latency performance in most of the considered cases. P-EFIT achieves full kinetic equilibrium reconstruction algorithms and repeats the EFIT results with the DIII-D internal Plasma current and kinetic profile measurements in one-percent cost time of EFIT. All these works suggest that P-EFIT can provide quality magnetic equilibrium reconstruction in real-time, offer full kinetic equilibrium reconstruction with high spatial resolution and high speed, support more detailed, better Plasma Control and data analysis for tokamak devices.
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overview of the preliminary design of the iter Plasma Control system
Nuclear Fusion, 2017Co-Authors: James A Snipes, Giampaolo Tommasi, Marcello Cinque, S Bremond, G Ambrosino, R Albanese, R Ambrosino, V Amoskov, T C Blanken, P De VriesAbstract:An overview of the preliminary design of the ITER Plasma Control system (PCS) is described here, which focusses on the needs for 1st Plasma and early Plasma operation in hydrogen/helium (H/He) up to a Plasma current of 15 MA with moderate auxiliary heating power in low confinement mode (L-mode). Candidate Control schemes for basic magnetic Control, including divertor operation and kinetic Control of the electron density with gas puffing and pellet injection, were developed. Commissioning of the auxiliary heating systems is included as well as support functions for stray field topology and real-time Plasma boundary reconstruction. Initial exception handling schemes for faults of essential plant systems and for disruption protection were developed. The PCS architecture was also developed to be capable of handling basic Control for early commissioning and the advanced Control functions that will be needed for future high performance operation. A Plasma Control simulator is also being developed to test and validate Control schemes. To handle the complexity of the ITER PCS, a systems engineering approach has been adopted with the development of a Plasma Control database to keep track of all Control requirements.
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conceptual architecture of the plant system Controller for the magnetics diagnostic of the iter tokamak
Fusion Engineering and Design, 2015Co-Authors: A Neto, S Arshad, F Sartori, G Vayakis, G Ambrosino, A J N Batista, Isidro Bas, Roberto Campagnolo, B B Carvalho, G De MagnevalAbstract:Abstract In a tokamak the magnetic diagnostics are key to the exploitation of the machine. They play a central role in the real-time Control of fundamental Plasma properties, such as the Plasma shape and position, while also contributing with important data to a better understanding of the Plasma physics. One of the particular challenges of the ITER magnetics diagnostic is the need to balance high system reliability with sufficient freedom to tune and improve the quality of the diagnostic physics output. This requirement calls for a design pattern where the functions related to Plasma Control and protection are loosely coupled with the functions related to the Plasma science. This work reports on the current status of the magnetics plant system Controller design and discusses some possible design solutions that address the aforementioned issue.
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the iter Plasma Control system simulation platform
Symposium On Fusion Technology, 2015Co-Authors: M.l. Walker, W Treutterer, Giampaolo Tommasi, D. A. Humphreys, G Neu, C Rapson, G Raupp, G Ambrosino, M Mattei, A.s. WelanderAbstract:Abstract The Plasma Control System Simulation Platform (PCSSP) is a highly flexible, modular, time-dependent simulation environment developed primarily to support development of the ITER Plasma Control System (PCS). It has been under development since 2011 and is scheduled for first release to users in the ITER Organization (IO) and at selected additional sites in 2015. Modules presently implemented in PCSSP enable exploration of axisymmetric evolution and Control, basic kinetic Control, and tearing mode suppression. A basic capability for generation of Control-relevant events is included, enabling study of exception handling in the PCS, continuous Controllers, and PCS architecture. While the Control design focus of PCSSP applications tends to require only a moderate level of accuracy and complexity in modules, more complex codes can be embedded or connected to access higher accuracy if needed. This paper describes the background and motivation for PCSSP, provides an overview of the capabilities, architecture, and features of PCSSP, and discusses details of the PCSSP vision and its intended goals and application. Completed work, including architectural design, prototype implementation, reference documents, and IO demonstration of PCSSP, is summarized and example use of PCSSP is illustrated. Near-term high-level objectives are summarized and include preparation for release of an “alpha” version of PCSSP and preparation for the next development phase. High-level objectives for future work are also discussed.
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a simulation environment for iter pcs development
Fusion Engineering and Design, 2014Co-Authors: M.l. Walker, W Treutterer, D. A. Humphreys, Gianmaria De Tommasi, G Raupp, G Ambrosino, M Mattei, A. WinterAbstract:Abstract A simulation environment known as the Plasma Control System Simulation Platform (PCSSP), specifically designed to support development of the ITER Plasma Control System (PCS), is currently under construction by an international team encompassing a cross-section of expertise in simulation and exception handling for Plasma Control. The proposed design addresses the challenging requirements of supporting the PCS design. This paper provides an overview of the PCSSP project and a discussion of some of the major features of its design. Plasma Control for the ITER tokamak will be significantly more challenging than for existing fusion devices. An order of magnitude greater performance (e.g. [1] , [2] ) is needed for some types of Control, which together with limited actuator authority, implies that optimized individual Controllers and nonlinear saturation logic are required. At the same time, consequences of Control failure are significantly more severe, which implies a conflicting requirement for robust Control. It also implies a requirement for comprehensive and robust exception handling. Coordinated Control of multiple competing objectives with significant interactions, together with many shared uses of actuators to Control multiple variables, implies that highly integrated Control logic and shared actuator management will be required. It remains a challenge for the integrated technologies to simultaneously address these multiple and often competing requirements to be demonstrated on existing fusion devices and adapted for ITER in time to support its operational schedule. We describe ways in which the PCSSP will help address these challenges to support design of both the ITER PCS itself and the algorithms that will be implemented therein, and at the same time greatly reduce the cost of that development. We summarize the current status of the PCSSP design task, including system requirements and preliminary design documents already delivered as well as features of the ongoing detailed architectural design. The methods being incorporated in the detailed design are based on prior experience with Control simulation environments in fusion and on standard practices prevalent in development of Control-intensive industrial product designs.
Stefan Kragh Nielsen - One of the best experts on this subject based on the ideXlab platform.
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the prospect for fuel ion ratio measurements in iter by collective thomson scattering
Nuclear Fusion, 2012Co-Authors: M. Stejner, Søren Bang Korsholm, Henrik Bindslev, Stefan Kragh Nielsen, Mirko Salewski, V Furtula, Frank Leipold, Poul Michelsen, F Meo, D MoseevAbstract:We show that collective Thomson scattering (CTS) holds the potential to become a new diagnostic principle for measurements of the fuel ion ratio, nT/nD, in ITER. Fuel ion ratio measurements will be important for Plasma Control and machine protection in ITER. Measurements of ion cyclotron structures in CTS spectra have been suggested as the basis for a new fuel ion ratio diagnostic which would be well suited for reactor environments and capable of providing spatially resolved measurements in the Plasma core. Such measurements were demonstrated in recent experiments in the TEXTOR tokamak. Here we conduct a sensitivity study to investigate the potential measurement accuracy of a CTS fuel ion ratio diagnostic on ITER. The study identifies regions of parameter space in which CTS can be expected to provide useful information on Plasma composition, and we find that a CTS fuel ion ratio diagnostic could meet the ITER measurement requirements for a standard ELMy H-mode discharge.
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Principles of fuel ion ratio measurements in fusion Plasmas by collective Thomson scattering
Plasma Physics and Controlled Fusion, 2011Co-Authors: M. Stejner, Søren Bang Korsholm, Henrik Bindslev, Stefan Kragh Nielsen, Mirko SalewskiAbstract:For certain scattering geometries collective Thomson scattering (CTS) measurements are sensitive to the composition of magnetically confined fusion Plasmas. CTS therefore holds the potential to become a new diagnostic for measurements of the fuel ion ratio?i.e. the tritium to deuterium density ratio. Measurements of the fuel ion ratio will be important for Plasma Control and machine protection in future experiments with burning fusion Plasmas. Here we examine the theoretical basis for fuel ion ratio measurements by CTS. We show that the sensitivity to Plasma composition is enhanced by the signatures of ion cyclotron motion and ion Bernstein waves which appear for scattering geometries with resolved wave vectors near perpendicular to the magnetic field. We investigate the origin and properties of these features in CTS spectra and give estimates of their relative importance for fuel ion ratio measurements.