V. Pericoli‐Ridolfini
A5049901788- Magnetic confinement fusion research
- Fusion materials and technologies
- Superconducting Materials and Applications
- Ionosphere and magnetosphere dynamics
- Particle accelerators and beam dynamics
- Laser-Plasma Interactions and Diagnostics
- Plasma Diagnostics and Applications
- Nuclear reactor physics and engineering
- Dust and Plasma Wave Phenomena
- Nuclear Materials and Properties
- Solar and Space Plasma Dynamics
- Laser-induced spectroscopy and plasma
- High-Energy Particle Collisions Research
- Gyrotron and Vacuum Electronics Research
- Ion-surface interactions and analysis
- Superconductivity in MgB2 and Alloys
- Physics of Superconductivity and Magnetism
- Advanced Photonic Communication Systems
- Nuclear and radioactivity studies
- Rocket and propulsion systems research
- Vibration and Dynamic Analysis
- Advanced Fiber Optic Sensors
- Advanced Surface Polishing Techniques
- Fluid Dynamics and Thin Films
- Radio Frequency Integrated Circuit Design
Institute of Plasma Physics and Laser Microfusion
2011-2020
Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Frascati
2016
National Agency for New Technologies, Energy and Sustainable Economic Development
2001-2014
Oak Ridge National Laboratory
2009
Sapienza University of Rome
2009
Culham Science Centre
2008
ENEA Frascati Research Centre
1998-2008
Queen's University Belfast
2005
CEA Cadarache
2004
Commissariat à l'Énergie Atomique et aux Énergies Alternatives
2004
Plasma exhaust has been identified as a major challenge towards the realisation of magnetic confinement fusion. To mitigate risk that single null divertor (SND) with high radiation fraction in scrape-of-layer (SOL) adopted for ITER will not extrapolate to DEMO reactor, EUROfusion consortium is assessing potential benefits and engineering challenges alternative configurations. Alternative configurations could be readily design include X (XD), Super-X (SXD), Snowflake (SFD) double (DND). The...
In order to simultaneously control the current and pressure profiles in high performance tokamak plasmas with internal transport barriers (ITB), a multi-variable model-based technique has been proposed. New algorithms using truncated singular value decomposition (TSVD) of linearized model operator retaining distributed nature system have implemented JET system. Their simplest versions applied density profile reversed shear three heating drive actuators (neutral beam injection, ion cyclotron...
Since the 2012 IAEA-FEC Conference, FTU operations have been largely devoted to runaway electrons generation and control, exploitation of 140 GHz electron cyclotron (EC) system liquid metal limiter elements. Experiments on shown that measured threshold electric field for their is larger than predicted by collisional theory can be justified considering synchrotron radiation losses. A new control algorithm was developed tested in presence a current plateau, allowing minimize interactions with...
Liquid lithium as a plasma-facing material was tested for the first time on high field medium size tokamak, FTU. A liquid Li reservoir supplies mesh of capillaries that is movable from shot to in scrape-off layer (SOL) plasma act secondary limiter. An almost complete lithization vacuum vessel walls obtained about three discharges. Plasmas cleaner than boronization and titanization, with lower radiation losses smaller impurity content are produced. The SOL electron temperature increases, ΔTe...
The recent development of real-time measurements and control tools in JET has enhanced the reliability reproducibility relevant ITER scenarios. Diagnostics such as charge exchange, interfero-polarimetry, electron cyclotron emission have been upgraded for measurements. In addition, processes like magnetic equilibrium q profile reconstruction developed applied successfully experiments using model based techniques. Plasma operation against magnetohydrodynamic instabilities are also benefiting...
Advanced scenario plasmas must often be run at low densities and high power, leading to hot edge temperatures consequent power handling issues plasma - surface interaction zones. Experiments ...
The first evidence of dust-impact ionization processes in the scrape-off layer Frascati tokamak upgrade (FTU) was reported Nucl. Fusion 47 L5 (2007) . In this work an extended data analysis (both electrostatic probe signals and surface analysis) is presented, using results empirical studies hypervelocity impacts. Within accuracy limits application such to plasma environment, are shown be consistent with occurrence impacts by micrometre size iron particles at velocities order 10 km s −1
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...
A 'hybrid' scenario for ITER is defined through its objectives: a large fusion yield long time duration. In many tokamaks, discharges characterized by stationary current density profile, enclosing volume of low magnetic shear with q(0) near 1, have achieved improved confinement and higher beta limits. Their extrapolation to from existing data corresponds the hybrid scenario. These are soft MHD events. Physics issues relevant existence this will be addressed. New JET experiments component RF...
A successful demonstration of real-time, model-based control the plasma current density profile has been made in JET. The safety factor was reconstructed using magnetic and polarimetric signals. Various predefined q-profile targets have reached—in least square approximation—using lower hybrid drive as only actuator, with a feedback loop measurements from five fixed normalized radii.
The experimental lower hybrid current drive efficiency at zero electric field is found to agree with theory if the spectrum of waves fully accessible central region plasma. For broad or very low parallel wave number spectra, N∥, for which plane accessibility condition not satisfied, observed higher than predicted. At non-zero field, measurements theories an dependent efficiency. model can also be applied experiments in a symmetric launched, cases where driven opposite DC runaway electrons...
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...
The frequency spectral broadening of lower hybrid (LH) waves injected into tokamak plasmas is extensively analysed with reference mostly to experimental data from the ASDEX tokamak. link between magnitude pump width and degradation LH current drive efficiency (up a factor 2), pointed out in previous works, explained. behaviour power absorption also well reproduced, even situations when access launched core plasma should be largely forbidden. Experiments are described that aimed at...
Steady internal transport barriers (ITBs) are obtained in FTU at ITER-relevant magnetic field and density (ne0 ≥ 1.3 × 1020 m−3) almost full non-inductive discharges, sustained by lower hybrid (LH) electron cyclotron (EC) RF waves sources. Similarly to ITER, only electrons directly heated which turn heat ions via collisions no momentum is injected. Collisions do not affect the mechanisms of turbulence suppression energy transport. At highest densities ion thermal conductivity remains ≤ ohmic...
Spontaneous increases in plasma density, up to ∼1.6 times the Greenwald value, are observed FTU with lithized walls. These plasmas characterized by profile peaking highest obtained densities. The transport analysis of these discharges shows a 20% enhancement energy confinement time, respect ITER97 L-mode scaling, correlated threshold factor. It has been found that 0.4 MW ECRH power, coupled at q = 2 surface, sufficient avoid disruptions 0.5 MA discharges. Direct heating magnetic islands...
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...
The recent success in coupling lower hybrid (LH) waves high performance plasmas at JET together with the first demonstration on FTU of capability new passive active multijunction launcher removed major concerns possibility using LH ITER. exhibits highest experimental current drive (CD) efficiency low plasma temperature thus making it natural candidate for off-axis CD ITER where profile control will help maintaining burning a long-time scale. We review results: long internal transport barrier...
The ITER hybrid scenario aims to exploit non-inductive current drive enable burn times in excess of 1000 s. To achieve this, and optimize fusion performance, requires high βN (the plasma pressure normalized a stability scaling) energy confinement equal or greater than that predicted for the baseline scenario. This paper discusses results from JET candidate scenario, where βN,MHD ⩽ 3.6 plasmas have been produced. Despite different initial phase, relevant parameters evolve rapidly towards...
An overall view of the phenomenology observed with radiofrequency (RF) probes during lower hybrid wave injection is presented for several operational regimes FT tokamak. The main emphasis on high plasma density regime where effects launched waves become negligible. A rather rich spectrum from about 0 MHz to beyond injected frequency in response RF pulse. Many secondary peaks, or sidebands, shifted pump by multiples ion cyclotron evaluated at outer torus edge appear, while strongly broadened....
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.
High-frequency wave systems with high-power density launching capability have been the preferred choice to heat Frascati Tokamak Upgrade (FTU) because of physics arguments (electron heating at very high density) and space constraints from compactness machine design (8-cm-wide port). They do include an 8-GHz lower hybrid current drive (LHCD) system, a 140-GHz electron cyclotron resonance (ECRH) 433-MHz ion Bernstein waves system (IBW). The technical aspects these will be reviewed in this...
The performance of divertor targets made liquid metal, either lithium or tin, in highly powered tokamaks is analyzed for the proposed European DEMO and projected Italian test tokamak (I-DTT). main tool 2D edge code TECXY, together with COREDIV. results show that both materials are compatible I-DTT under proper setting parameters. In general, operation at a high density always recommended especially if detached conditions desired. latter can be closely approached even when preserving an...