A5078826185- Magnetic confinement fusion research
- Plasma Diagnostics and Applications
- Particle accelerators and beam dynamics
- Dust and Plasma Wave Phenomena
- Laser-induced spectroscopy and plasma
- Ionosphere and magnetosphere dynamics
- Atomic and Molecular Physics
- Cold Atom Physics and Bose-Einstein Condensates
- Nonlinear Waves and Solitons
- Physics of Superconductivity and Magnetism
- Laser-Plasma Interactions and Diagnostics
- Fusion materials and technologies
- Electrostatic Discharge in Electronics
- Nuclear reactor physics and engineering
- Nuclear Materials and Properties
- Catalytic Processes in Materials Science
- Geophysical and Geoelectrical Methods
- Aerosol Filtration and Electrostatic Precipitation
- Climate Change Policy and Economics
- Superconducting Materials and Applications
- European Monetary and Fiscal Policies
- Quantum chaos and dynamical systems
- Nonlinear Photonic Systems
- Graphite, nuclear technology, radiation studies
- Radiation Effects in Electronics
San Jose State University
2023
University Transportation Research Center
2023
University Transportation Centers Program
2023
Max Planck Institute for Plasma Physics
2018
Max Planck Society
2018
École Polytechnique Fédérale de Lausanne
1982-2017
This paper describes the progress of DEMO Design Activities in Europe and particularly work done to address critical design integration issues that affect machine configuration performance, plant concept layout selection system technologies. Work continues be primarily focused on a pulsed baseline reactor concept, but number alternative configurations (e.g., double-null divertor snowflake as well ‘flexi’ operates initially an inductively driven regime, with possibility upgraded long-pulse or...
This paper describes the progress of DEMO design and R&D activities in Europe. The focus is on a systems engineering integration approach, which recognized to be essential from an early stage identify address operational challenges, requirements for technology physics R&D. We present some preliminary choices/sensitivity studies explore narrow down space identify/select attractive points. also discuss initial results work being executed EUROfusion Consortium by geographically distributed...
We present a fully-implicit electromagnetic Particle-In-Cell Monte Carlo collision code, called NINJA, written for the simulation of inductively coupled plasmas. NINJA employs kinetic enslaved Jacobian-Free Newton Krylov method to solve self-consistently interaction between field generated by radio-frequency coil and plasma response. The simulated includes description charged neutral species as well processes them. algorithm allows simulations with cell sizes much larger than Debye length...
A Korteweg-de Vries equation for a two component-plasma with cold ions (Ti=0 both species) and isothermal electrons has been derived. The amplitude of the solitons is reduced drastically by few percent light an initial perturbation breaks up into more than in one component plasma.
The $\mathbf{E}\ifmmode\times\else\texttimes\fi{}\mathbf{B}$ rotation and associated collisional ion heating of noble-gas magnetized plasmas are investigated with high resolution by means laser-induced fluorescence electrical probes. Plasma results from a radial potential gradient which can be controlled biasing the discharge electrodes. time space evolution potential, velocity ${v}_{\ensuremath{\theta}}$, perpendicular temperature indicate that is due to randomization...
Stochastic acceleration of plasma ions is observed in the field an intense electrostatic wave. Both ion cyclotron and Bernstein waves are launched from antennas at boundary, motions by laser-induced fluorescence. The threshold for stochastic heating first time. As anticipated, distribution function changes rapidly above (on a cyclotron-period time scale). Measurements wave electric indicate that responsible accelerations.
The problem of the linear conversion a Langmuir wave to transverse electromagnetic in presence density gradient has been solved numerically with appropriate boundary conditions. A reciprocity principle was found, allowing deduction solutions this from those obtained transverse-Langmuir conversion. This model applied study spectrum emitted an inhomogeneous plasma, including effect antenna radiation pattern. Experiments have performed large unmagnetized dc discharge plasma (ne∼5×1010 cm−3, Te...
Linear, nondispersive ion acoustic wave propagation in an argon-helium plasma is investigated a double device. The experimental patterns show that there exists range of light concentration $\ensuremath{\alpha}$ where both argon and helium modes can be excited propagate simultaneously, contrary to previously published experiment Nakamura et al. phase velocity the mode only slightly affected by presence He ions. In case wave, it described reduced mass...
Using a Korteweg-de Vries equation the author studies propagation of ion acoustic solitary waves in two species plasma. As dispersion relation presents branches with quite different phase velocities, types soliton can propagate: slow one which is subsonic respect to mode and supersonic other, has greater amplitude smaller width than fast one.
In the EU DEMO design (Romanelli, 2012; Federici et al., 2014), due to large number of complex systems inside tokamak vessel it is vital importance address in-vessel integration at an early stage in process. design, after a first phase which different have been developed independently based on defined baseline configuration, effort has made define interface requirements and propose strategies for mechanical auxiliary heating fuelling into Vacuum Vessel Breeding Blanket. This work presents...
For a dedicated performance optimization of negative hydrogen ion sources applied at particle accelerators, detailed assessment the plasma processes is required. Due to compact design these sources, diagnostic access typically limited optical emission spectroscopy yielding only line-of-sight integrated results. In order allow for spatially resolved investigation, electromagnetic particle-in-cell Monte Carlo collision code NINJA has been developed Linac4 source CERN. This considers RF field...
Inductively Coupled Plasmas (ICP) are well known to exhibit two modes of operation: a low density capacitive E-mode and high inductive H-mode.In this study we investigate the E-H transition in cylindrical ICP, show e↵ect an external magnetic cusp field on dynamics.The plasma is simulated by Electro-Magnetic Particle-In-Cell Monte Carlo Collision code order take into account spatio-temporal variations dynamics as kinetic e↵ects.Simulations compared photometry measurements Linac4 H ion source...
Chaos generated by the interaction between charged particles and electrostatic plasma waves has been observed in a linear magnetized plasma. The macroscopic wave properties, kinetic ion dielectric response, microscopic heating mechanisms have investigated via optical diagnostic techniques based on laser-induced fluorescence. Observations of test-particle dynamical evolution indicate an exponential separation initially close trajectories.
The formation of ion acoustic solitons in an argon-helium plasma is studied as a function the light-ion concentration. It found that initial perturbation does not break into for $1%\ensuremath{\lesssim}\ensuremath{\alpha}\ensuremath{\lesssim}66%$. This fact can be related to increase linear Landau damping and nonlinear resonant particles, i.e., reflected ions front potential hump eventually trapped between two solitons. In concentration range where are formed (essentially...
The power requirements of RF heated sources for negative hydrogen ions in fusion are substantial, which poses strong demands on the generators and components circuit. Consequently, an increase coupling efficiency would be highly beneficial. Fundamental investigations inductively coupled deuterium discharges cylindrical symmetry conducted at lab experiment CHARLIE. is equipped with several diagnostics including optical emission spectroscopy a movable floating double probe to monitor plasma...
This paper presents a Particle-In-Cell Monte Carlo Collision simulation of the Radio-Frequency (RF) plasma heating in Linac4 H− ion source at CERN. The model self-consistently takes into account electromagnetic field generated by RF coil, external static magnetic fields and resulting response, including kinetic description charged species (e−, H+, H2+, H3+, H−), as well atomic molecular (vibrationally resolved) populations. is performed for nominal operational condition 40 kW power 3 Pa H2...
Ion orbits are followed in phase space by means of a new scheme the optical tagging plasma diagnostic technique. An orbit distortion for ions interacting resonantly with an ion acoustic wave is clearly observed even low excitation regime, where response and corresponding macroscopic fields exhibit linear behavior.
Cross-field transport of barium test ions is studied in a Q-machine plasma. Test particles are produced and tracked their motion by an optical tagging method. The comparison between the measured tag signal simple theoretical simulation yields evaluation ion diffusivity. Diffusion supported classical mechanisms. injection different noble buffer gases modifies plasma parameters such way that diffusion remains but its magnitude reduced.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML"...
A study of the application high-order TM0m0 modes a cylindrical cavity to measurement density magnetized plasma column is presented. It shown theoretically that judiciously chosen have potential advantages both wide operational range densities, and for which simple perturbation theory valid. Furthermore, an experiment described shows TM060 mode can be excited with sufficiently high Q value allow accurate determination resonant frequencies, hence density. Favorable comparison between...