Publications de Riccardo Agnello

Publications associées (46)

Negative ion characterization in a helicon plasma source for fusion neutral beams by cavity ring-down spectroscopy and Langmuir probe laser photodetachment

Ivo Furno, Alan Howling, Gennady Plyushchev, Philippe Frédérique Bruno Guittienne, Riccardo Agnello, Rémy Jacquier

Negative ions are characterized in the helicon plasma source resonant antenna ion device (RAID) at the Swiss plasma center by means of cavity ring-down spectroscopy (CRDS) and Langmuir probe (LP)-assisted laser photodetachment. A high density and axially h ...

IOP Publishing Ltd2020

A double-ended helicon source to symmetrize RAID plasma

Ivo Furno, Alan Howling, Riccardo Agnello, Marcelo Baquero Ruiz, Philippe Frédérique Bruno Guittienne, Rémy Jacquier, Christine Stollberg, Renat Karimov, Simon Pierre Henri Vincent

Neutral Beam Injectors (NBI) for post-DEMO-like reactors must achieve a neutralization efficiency (fraction neutrals/ions) above 70%. To reach this, NBIs based on negative ions are necessary and an innovative concept of this type of injector is based on ph ...

2023

H0LiCOW-IX. Cosmographic analysis of the doubly imaged quasar SDSS 1206+4332 and a new measurement of the Hubble constant

Frédéric Courbin, Georges Meylan, Hung-Hsu Chan, Riccardo Agnello, Vivien François Bonvin

We present a blind time-delay strong lensing (TDSL) cosmographic analysis of the doubly imaged quasar SDSS 1206+4332. We combine the relative time delay between the quasar images, Hubble Space Telescope imaging, the Keck stellar velocity dispersion of the ...

OXFORD UNIV PRESS2019

Highlights of recent SPIDER results and improvements

Riccardo Agnello, Basile Marie Jacques Pouradier Duteil

Three years of experiments on SPIDER allowed characterization of the main features of the source plasma and of the negative ion beam, in the original design configuration. For the large dimensions of the source chamber, and of the extraction area, the inve ...

2023

Optimizing the ITER NBI ion source by dedicated RF driver test stand

Riccardo Agnello

The experimental fusion reactor ITER will feature two (or three) heating neutral beam injectors (NBI) capable of delivering 33(or 50) MW of power into the plasma. A NBI consists of a plasma source for production of negative ions (extracted negative ion cur ...

Institute of Physics2024

Numerical and experimental investigations of a microwave interferometer for the negative ion source SPIDER

Ivo Furno, Rémy Jacquier, Riccardo Agnello

The electron density close to the extraction grids and the co-extracted electrons represent a crucial issue when operating negative ion sources for fusion reactors. An excessive electron density in the plasma expansion region can indeed inhibit the negativ ...

IOP Publishing Ltd2023

Negative hydrogen ion dynamics inside the plasma volume of a linear device: Estimates from particle-in-cell calculations

Ivo Furno, Alan Howling, Philippe Frédérique Bruno Guittienne, Rémy Jacquier, Riccardo Agnello

Negative hydrogen or deuterium ions are the precursor particles used to generate a high power beam of neutrals in order to heat the tokamak plasma core of magnetic fusion devices, inject current, and to some extent control instabilities. In the case of ITE ...

2021

The STRong lensing Insights into the Dark Energy Survey (STRIDES) 2016 follow-up campaign - I. Overview and classification of candidates selected by two techniques

Frédéric Courbin, Georges Meylan, Eduardo Sanchez, Craig Matthew Smith, Hung-Hsu Chan, Riccardo Agnello, Joo Yeon Kim, Augusto Martins Lima, Karina Alexandra Rojas Olate, Cameron Alexander Campbell Lemon

The primary goals of the STRong lensing Insights into the Dark Energy Survey (STRIDES) collaboration are to measure the dark energy equation of state parameter and the free streaming length of dark matter. To this aim, STRIDES is discovering strongly lense ...

OXFORD UNIV PRESS2018

Characterization of cesium and H-/D- density in the negative ion source SPIDER

Riccardo Agnello

The Heating Neutral Beam Injectors (HNBs) for ITER will have to deliver 16.7 MW beams of H/D particles at 1 MeV energy. The beams will be produced from H -/D- ions, generated by a radiofrequency plasma source coupled to an ion acceleration system. A protot ...

2023

Measurement of stripping losses in the negative ion source SPIDER

Riccardo Agnello

The negative ion source SPIDER at Consorzio RFX (Italy) is a crucial experimental step towards the development of the Heating Neutral Beam (HNB) injectors for ITER. The goal of SPIDER is to operate and optimize a full-scale negative ion source in hydrogen ...

ELSEVIER SCIENCE SA2023

Application of Thomson scattering to helicon plasma sources

Ivo Furno, Patrick Blanchard, Alan Howling, Yanis Andrebe, Riccardo Agnello, Rémy Jacquier, Hugo Antoine Georges Arnichand, Alban Sublet

The possibility of performing electron density and temperature measurements in a high power helicon plasma is a crucial issue in the framework of the AWAKE (Advanced WAKefield Experiment) project, which demonstrates acceleration of particles using GeV m(-1 ...

Cambridge University Press2020

Laser photo-detachment combined with Langmuir probe in magnetized electronegative plasma: how the probe size affects the plasma dynamic?

Ivo Furno, Riccardo Agnello

Laser photo-detachment combined with a Langmuir probe (LP) is used to diagnose negative ion properties in electronegative plasmas. The technique relies on the combined use of a laser pulse and an LP. The laser pulse converts negative ions into electron-ato ...

2021

Simulation and experimental study of proton bunch self-modulation in plasma with linear density gradients

Ambrogio Fasoli, Sun Hee Kim, Ivo Furno, Patrick Blanchard, Yanis Andrebe, Riccardo Agnello, Alban Sublet, Falk Hans Braunmüller, Christine Stollberg

We present numerical simulations and experimental results of the self-modulation of a long proton bunch in a plasma with linear density gradients along the beam path. Simulation results agree with the experimental results reported [F. Braunmller, T. Nechae ...

2021

Spectroscopic characterisation of H2 and D2 helicon plasmas generated by a resonant antenna for neutral beam applications in fusion

Basil Duval, Ivo Furno, Alan Howling, Alexander Karpushov, Philippe Frédérique Bruno Guittienne, Rémy Jacquier, Riccardo Agnello, Gennady Plyushchev, Kevin Henricus Annemarie Verhaegh, Claudio Marini

A new generation of neutral beam systems will be required in future fusion reactors, such as DEMO, able to deliver high power (up to 50 MW) with high (800 keV or higher) neutral energy. Only negative ion beams may be able to attain this performance, which ...

IOP Publishing Ltd2017

Vibrational excitation and dissociation of deuterium molecule by electron impact

Ivo Furno, Riccardo Agnello

A theoretical investigation of electron-D-2 resonant collisions-via the low-lying and the Rydberg states of D-2(-)-is presented for vibrational excitation, dissociative electron attachment and dissociative excitation processes by using the local-complex-po ...

2021

Latest experimental and theoretical advances in the production of negative ions in caesium-free plasmas

Ivo Furno, Alan Howling, Riccardo Agnello, Philippe Frédérique Bruno Guittienne, Rémy Jacquier, Samir Suweis

This topical review gathers the last updates concerning caesium-free negative ion sources presented during the 63rd Course of the International school of Quantum Electronics of the Ettore Majorana Foundation and European collaborative works related to thes ...

2021

Negative ion source development for a photoneutralization based neutral beam system for future fusion reactors

Basil Duval, Ivo Furno, Alan Howling, Philippe Frédérique Bruno Guittienne, Rémy Jacquier, Riccardo Agnello, Claudio Marini

In parallel to the developments dedicated to the ITER neutral beam (NB) system, CEA-IRFM with laboratories in France and Switzerland are studying the feasibility of a new generation of NB system able to provide heating and current drive for the future DEMO ...

Iop Publishing Ltd2016

Development and first operation of a cavity ring down spectroscopy diagnostic in the negative ion source SPIDER

Riccardo Agnello

The neutral beam injectors of the ITER experiment will rely on negative ion sources to produce 16.7 MW beams of H/D particles accelerated at 1 MeV. The prototype of these sources was built and is currently operated in the SPIDER (Source for the Production ...

2021

On the road to ITER NBIs: SPIDER improvement after first operation and MITICA construction progress

Riccardo Agnello, Basile Marie Jacques Pouradier Duteil

To reach fusion conditions and control the plasma configuration in ITER, the next step in tokamak fusion research, two neutral beam injectors (NBIs) will supply 16.5 MW each, by neutralizing accelerated negative hydrogen or deuterium ions. The requirements ...

2021

Continuous pulse advances in the negative ion source NIO1

Riccardo Agnello, Basile Marie Jacques Pouradier Duteil

Consorzio RFX and INFN-LNL have designed, built and operated the compact radiofrequency negative ion source NIO1 (Negative Ion Optimization phase 1) with the aim of studying the production and acceleration of H- ions. In particular, NIO1 was designed to ke ...

2023