P. Micozzi
A5053964533- Magnetic confinement fusion research
- Ionosphere and magnetosphere dynamics
- Superconducting Materials and Applications
- Particle accelerators and beam dynamics
- Fusion materials and technologies
- Laser-Plasma Interactions and Diagnostics
- Solar and Space Plasma Dynamics
- Plasma Diagnostics and Applications
- Quantum, superfluid, helium dynamics
- Atomic and Subatomic Physics Research
- Gyrotron and Vacuum Electronics Research
- Astro and Planetary Science
- Geomagnetism and Paleomagnetism Studies
- Nuclear reactor physics and engineering
- Physics of Superconductivity and Magnetism
- Refrigeration and Air Conditioning Technologies
- Advancements in Semiconductor Devices and Circuit Design
- Nonlinear Dynamics and Pattern Formation
- Astrophysics and Star Formation Studies
- Advanced X-ray and CT Imaging
- Dust and Plasma Wave Phenomena
- Quantum chaos and dynamical systems
- Drilling and Well Engineering
- Quantum and electron transport phenomena
- Nuclear Materials and Properties
National Agency for New Technologies, Energy and Sustainable Economic Development
2009-2024
Electron temperatures in excess of 8 keV have been obtained by electron-cyclotron-resonance heating on FTU plasmas at peak densities up to $8\ifmmode\times\else\texttimes\fi{}{10}^{19}\mathrm{m}{}^{\ensuremath{-}3}$. The magnetic shear the plasma core is low or negative, and electron heat diffusivity remains at, below, Ohmic level $(0.2\mathrm{m}{}^{2}/\mathrm{s})$, spite very large power density $(10--20\mathrm{MW}/\mathrm{m}{}^{3})$ which produces extremely high temperature gradients (up...
Several improvements to the MAST plant and diagnostics have facilitated new studies advancing physics basis for ITER DEMO, as well future spherical tokamaks (STs). Using increased heating capabilities P NBI ⩽ 3.8 MW H-mode at I p = 1.2 MA was accessed showing that energy confinement on scales more weakly with strongly B t than in IPB98( y , 2) scaling. Measurements of fuel retention shallow pellets extrapolate an particle throughput 70% its original designed total capacity. The anomalous...
Studies on the current-drive (CD) efficiency have been carried out in FTU tokamak with 8 GHz lower-hybrid waves up to line-averaged plasma density ${\overline{n}}_{e}>1\ifmmode\times\else\texttimes\fi{}{10}^{20}{\mathrm{m}}^{\ensuremath{-}3}$. High efficiencies, larger than $0.2\ifmmode\times\else\texttimes\fi{}{10}^{20}{\mathrm{m}}^{\ensuremath{-}2}\mathrm{A}/\mathrm{W}$, are obtained for clean conditions, no significant degradation as is increased accessibility limit. The electron...
Plasma behaviour in the high density regime has been investigated on Frascati Tokamak Upgrade (FTU). The items particularly addressed are limit, MARFE characteristics and fuelling efficiency. With gas puffing, a maximum line average of 3.2*1020 m-3 obtained ohmic at q=5.1, corresponding to 1.7 times Greenwald limit; while with pellet injection, value 3.7*1020 reached q=3.5. limit appears be connected impurity content edge parameters, so best results very clean plasmas peaked electron...
Over the last few years, a great deal of effort has been devoted to solving problem power and particle handling in divertors, which recognized as critical issue for operation magnetic fusion reactor. In particular, choice materials plasma facing components examined with view developing heat erosion resistant divertor target plates. A large database on behaviour low-Z (carbon or beryllium) tokamaks is available, while high-Z there little experience present generation devices. Frascati Tokamak...
Substantial advances have been made on the Mega Ampère Spherical Tokamak (MAST). The parameter range of MAST confinement database has extended and it now also includes pellet-fuelled discharges. Good pellet retention observed in H-mode discharges without triggering an ELM or H/L transition during peripheral ablation low speed pellets. Co-ordinated studies DIII-D demonstrate a strong link between aspect ratio beta scaling energy confinement, consistent with that obtained when data were merged...
The design study of PROTO-SPHERA, a novel compact torus configuration, has been completed. It is composed spherical (ST) (with closed flux surfaces) and force-free screw pinch (SP) open surfaces fed by electrodes). PROTO-SPHERA formed at spherical-tokamak-like densities (∼1019 m−3) with low voltage (∼200 V) between the electrodes. idea replacing metal centrepost current (Itf) tokamaks SP plasma electrode (Ie) aimed mainly getting rid rod centre which most critical component tokamak design....
Experiments with different dominant impurities (C, Si, Ni, Mo) have been carried out on the FTU tokamak. Density limit, marfe, Zeff and radiation losses are compared discussed. An analytical model that couples in a self consistent way parameters of SOL transport generated at limiter to bulk plasma has used reproduce experimental data.
The MHD activity of plasma configurations with reversed magnetic shear has been investigated on the FTU tokamak. In presence pairs surfaces same rational value q = m/n safety factor, double-tearing modes are excited which give rise in most cases to bursts sawtooth-like profile rearrangements. More stable regimes have also found, is dominated by rotating saturated modes. a particular case and discharge without any detectable during current flat-top obtained. high-temperature ( at ), an...
High density plasmas (n0 ≈ 8 × 1020m-3) featuring steady improved core confinement have been obtained in FTU up to the maximum nominal toroidal field (8 T) by deep multiple pellet injection. These also feature high purity efficient electron-ion coupling and peaked profiles sustained for several times. Neutron yields excess of 1 1013 n/s are measured, consistent with reduction ion transport neoclassical levels.
Plasma properties can be useful in a wide spectrum of applications. Experimental projects on controlled nuclear fusion are the most challenging these applications and, at same time, best way to approach plasma science. Since reactors ensure large-scale, safe, environmentally-friendly and virtually inexhaustible source energy, several fusion-oriented megaprojects innovative companies appearing all over world. PROTO-SPHERA (Spherical for HElicity Relaxation Assessment) is first project with...
Operating with a high frequency and wave guide antenna, the ion Bernstein (IBW) experiment on Frascati Tokamak Upgrade is not dominated, as expected, by nonlinear plasma edge phenomena. By coupling IBW power, simultaneous increase of density central electron temperature (⩾2 keV) produced when confinement magnetic field adjusted to set an cyclotron resonant layer in bulk. Transport analysis indicates reduction thermal transport inside internal larger than factor 2.
The behaviour of the FTU tokamak plasma has been analysed by using two reconstructive MHD equilibrium codes: first code works magnetic data alone and second one including as well shape kinetic pressure profile, obtained from measured profiles electron temperature Te density ne. that analyses provides a good evaluation macroscopic quantities such poloidal beta βp internal inductance li, if elongation is greater than 1.04. No detailed information about toroidal current profile Jϕ safety factor...
The localized electron cyclotron resonance heating power that can suppress sawteeth reconnection often drives m = 2 tearing modes in a tokamak operating at constant current. dynamics of mode onset and coupled evolution is described detail compared with nonlinear theoretical model identifies the effects coupling, finite inertia rotating islands, wall braking.
A scanning interferometer has been developed and installed on the FTU tokamak for plasma density profile measurements. system is equivalent to a multi-chord while keeping optical scheme as simple single-chord interferometer. This new diagnostic achieved spatial resolution of ~1 cm time 62 μs. In this paper, we present first measurements carried out with showing its peculiar capabilities. Particular care paid analysis pellet fuelled discharges, where fast large change (1021 m−3 in 100 μs)...
Magnetohydrodynamic (MHD) activity and energy transport at rational-q surfaces is analysed on the basis of experimental results current density profile control obtained with localized electron cyclotron resonance heating (ECRH) FTU tokamak. The MHD response, in particular 2/1 1/1 modes, to ECRH agreement expectations from a theoretical model including resistive wall braking toroidal mode coupling. It also shown that magnetic shear rq = 1 could m saturation reconnection. Heating steady state...
The role of magnetic shear in affecting electron transport is discussed on the basis Frascati tokamak upgrade (FTU) data with central cyclotron resonance heating (ECRH) current ramp phase and pellet injection. results point out that strongly negative not a necessary condition order to have good magnetohydrodynamic (MHD) activity plays crucial region low/negative shear. theoretical arguments for dependence are reviewed compared experimental evidence.
The PROTO-SPHERA experiment (under construction in Frascati inside the START vacuum vessel) aims to study properties of a spherical torus (ST), where hydrogen force-free screw pinch (SP, with open field lines and fed by electrodes) replaces central rod standard tokamak experiments: PROTO-SPHERA, current I e = 60 kA, at producing (with closed lines) diameter 2 R sph 70 cm, aspect ratio / A 1.2–1.3, carrying toroidal p 120–240 kA. Such configuration is an evolution flux core spheromak (FCS)...
The study sets out to investigate the parts of FTU operating space over which pellet injection effects performance improvement and elucidate phenomena hinder it. In this respect behaviour q=1 resonance is found play most relevant role.
Three methods of density modulation have been used in FTU discharges (gas puffing, pellet injection and current rampup). The analysis particle balance confirms that the neoclassical theory is not adequate experimental results obtained by three are to verify validity an empirical expression for radial flux. Such relevant design future experiments constitutes a constraint any satisfactory
The filament state of a magnetic field is the usual way for plasmas to avoid inhibition convective overturning. However, it requires dynamo conversion kinetic into energy and therefore often associated with plasma velocity shear layer. In sun, isolated current carrying filaments (twisted flux tubes) are produced by solar from continuous strong toroidal field, sitting just below radiative–convective transition, on Sun rotation layer (tachocline, rTach ∼ 2 · R⊙/3 in terms radius, R⊙). twisted...
Abstract In astrophysics, the boundary conditions for plasma phenomena are provided by nature and astronomer faces problem of understanding them from a variety observations [Hester J et al 1996 Astrophys. J. 456 225], on other hand, in laboratory experiments electromagnetic become major set-up machine that produces plasma, an issue has to be investigated step modified adapted with great patience, particular case innovative confinement experiment. The PROTO-SPHERA [Alladio F 2006 Nucl. Fusion...
Magnetic coordinates (ψT=radial label of flux surfaces, θ=poloidal, and ϕ=toroidal angle) are introduced in toroidal magnetoplasma equilibria order to straighten the field lines [described by: θ−ι̷(ψT)ϕ=constant on any surface, ι̷(ψT) being rotational transform]. The simplest method for analyzing ideal magnetohydrodynamic (MHD) stability expands perturbed plasma displacement ξ⃗ magnetic solves normal mode equation through one-dimensional (1D) radial finite elements. This paper extends...
An exact prediction of the plasma contour is important for design new tokamaks and definition operational scenarios existing machines. Certain features boundary, such as elongation triangularity, a detailed description X-point region are relevant plasma-limiter interaction. The toroidal multipolar moment method has been used, with fixed boundary conditions, to produce required shape. resulting vacuum flux function reproduced, using poloidal coil currents that minimize magnetic energy best...