A5013919327- Particle accelerators and beam dynamics
- Magnetic confinement fusion research
- Plasma Diagnostics and Applications
- Superconducting Materials and Applications
- Particle Accelerators and Free-Electron Lasers
- Atomic and Molecular Physics
- Fusion materials and technologies
- Gyrotron and Vacuum Electronics Research
- Nuclear Physics and Applications
- Muon and positron interactions and applications
- Atomic and Subatomic Physics Research
- Acoustic Wave Resonator Technologies
- Silicon Carbide Semiconductor Technologies
- Laser-Plasma Interactions and Diagnostics
Max Planck Institute for Plasma Physics
2015-2023
Max Planck Society
2015-2021
University of Padua
2015
The European DEMO is a pulsed device with pulse length of 2 hours. functions devoted to the heating and current drive system are: plasma breakdown, ramp-up flat-top where fusion reactions occur, control during phase, finally ramp-down. EU-DEMO project was in Pre-Concept Design Phase 2014-2020, meaning that some cases, design values precise requirements from physics point view were not yet frozen. A total 130 MW considered for all phases plasma: flat top, 30 required neoclassical tearing...
Abstract For the D-T operational phase of international fusion experiment ITER, starting in 2035, pulses are planned with Q > 10 and a duration 400 s = 5 for up to 3600 s. The two neutral beam injection (NBI) systems will deliver 33.3 MW heating power plasma also be an important source non-inductive current drive. An essential part NBI is large RF driven negative hydrogen or deuterium ions. In order fulfil requirements imposed system, ion has intense, stable homogeneous over pulse lengths...
Negative ion sources for neutral beam injection (NBI) in fusion experiments are based on the surface production of H− or D− cesiated low work function surfaces. In recent years, it was demonstrated at large RF driven source ELISE (Extraction from a Large Ion Source Experiment) test facility that requirements ITER NBI systems can be fulfilled by hydrogen. This is big step toward first operational period ITER, planned up to 2035. However, following period, working deuterium needed. Operation...
The knowledge of Cs dynamics in negative hydrogen ion sources is a primary issue to achieve the ITER requirements for Neutral Beam Injection (NBI) systems, i.e. one hour operation with an accelerated current 40 A D− and ratio between ions co-extracted electrons below one.Production mostly achieved by conversion hydrogen/deuterium atoms on converter surface, which caesiated order reduce work function increase efficiency. understanding transport redistribution mechanism inside source necessary...
Large negative ion sources for neutral beam injection rely on surface production of ions a converter (plasma grid) in low temperature plasma environment. To increase the efficiency and reduce amount co-extracted electrons, work function grid is reduced by using Cs, which evaporated source redistributed inner surfaces. In order to avoid degradation during pulses sufficient flux Cs onto needs be maintained, especially long (several hundred seconds). The influenced distribution source, can...
Negative ion sources for fusion rely on the formation of negative hydrogen (or deuterium) ions by conversion atomic and positive at a low work function caesiated surface. Cs is thus evaporated into source to decrease surface function, which may change due removal redistribution during plasma phases. To maintain temporarily stable 1 h plasma, continuous evaporation caesium required, this performed temperature controlled ovens. The ovens ELISE (IPP Garching) SPIDER (Consorzio RFX) are based...
The negative hydrogen ion current that can be extracted from sources for neutral beam heating in fusion experiments strongly restricted by the amount of co-extracted electrons and their increase over time, particularly during long pulses (up to 1 h). Models describing underlying physics particle extraction a low-temperature plasma with high ions are essential identifying measures reducing stabilizing electrons. In this work, 3D PIC-MCC code ONIX (Orsay Negative Ion eXtraction) volume around...
The large RF negative hydrogen (deuterium) ion source at the ELISE test facility (half of ITER-NBI size) has been equipped with a Cavity Ring-Down Spectroscopy (CRDS) system, in order to measure density region front plasma grid (first extraction system). challenge this diagnostic for relies on size and therefore length across which measurements are performed as well long pulses power, can affect cavity mirror reliability. A dedicated experiment reliability was performed, ensuring feasibility...
For the ITER fusion experiment, two neutral beam injectors are required for plasma heating and current drive. Each injector supplies a power of about 17 MW, obtained from neutralization 40 A (46 A), 1 MeV (0.87 MeV) negative deuterium (hydrogen) ions. The full is composed 1280 beamlets, formed in 16 beamlet groups, strict requirements apply to core divergence (<7 mrad). test facility BATMAN Upgrade uses an ITER-like grid with one group, which consists 70 apertures. In joint campaign...
Abstract The ITER NBI is based on negative hydrogen ions extracted from caesiated ion sources. 3D particle-in-cell Monte Carlo collision code Orsay extraction (ONIX) models the beamlet formation of in such sources where surface production plays an important role. A coupling scheme between ONIX and ion-optics beam simulator (IBSimu) has been developed compared to other particle simulation approaches. This extends computational domain that complete grid system can be included while only...
Abstract The large ion source of ITER’s neutral beam injection (NBI) systems (0.9 m×1.9 m) with 1280 apertures has to deliver 57 A D - for 3600 s (286 A/m 2 ) and 66 H 1000 (329 ). RF test facilities ELISE BUG at IPP are aimed demonstrate the parameters, homogeneity beams (up 1 m×1 perform optic studies. While ITER parameters could be demonstrated in hydrogen, achievement deuterium long pulses is still pending due fraction co-extracted electrons, their temporal dynamics, inhomogeneity...
The Neutral Beam Injection (NBI) system for fusion devices like ITER and, beyond ITER, DEMO requires large scale sources negative hydrogen ions. BATMAN (Bavarian Test Machine Negative ions) is a test facility attached with the prototype source NBI (1/8 size of source), dedicated to physical investigations due its flexible access diagnostics and exchange components. required amount ions produced by surface conversion atoms or on caesiated surfaces. Several diagnostic tools (Optical Emission...
Enhancement of negative ion sources for production large beams is a very active research field nowadays, driven from demand plasma heating in nuclear fusion devices and accelerator applications. As versatile test bench, the source NIO1 (Negative Ion Optimization 1) being commissioned by Consorzio RFX INFN. The nominal beam current 135 mA at −60 kV divided into 9 beamlets, with multiaperture extraction electrodes. sustained 2 MHz radiofrequency power supply, standard matching box. A High...
The radio frequency ion source NIO1, jointly developed by Consorzio RFX and INFN-LNL, will generate a 60kV-135mA hydrogen negative beam, composed of 9 beamlets over an area about 40 × mm2. This experiment operate in continuous mode conditions similar to those foreseen for the larger sources Neutral Beam Injectors ITER. modular design NIO1 is convenient address several still open important issues related beam extraction, optics, performance optimization. To this purpose set diagnostics being...
Abstract The ITER neutral beam injection system for heating and current drive requires Negative Ions (NI) produced in large ceasiated ion sources. Self-consistent 3D Particle-In-Cell Monte-Carlo Collision (PIC-MCC) modelling is necessary simulating extraction of NI the co-extraction electrons ITER-like In RF driven negative sources at ELISE BUG test facilities, filter field generated by a drawn through Plasma Grid (PG). PIC-MCC code ONIX has been used to study role electron temperature,...
Abstract An H - ion source is being operated at the new 160 MeV linear injector (Linac4) of CERN accelerator complex. The source’s plasma Radio Frequency Inductively Coupled Plasma type (RF-ICP), without magnetic cusp and runs with Cs-loss compensation [1]. Vertical downward oriented filter- electron dump-dipolar fields expand over chamber, beam-formation, beam-extraction dump regions generate horizontal asymmetry beam angular deflection partially compensated by mechanical alignment...
Beam extraction at the large ELISE test facility is currently possible only pulsed, with short phases, so-called blips, of up to 10 s each ≈150 s. Over past years, a good insight into physics this operational mode has been gained for both hydrogen and deuterium operation. The uniformity co-extracted electrons was identified as key issue it achieve 1000 plasma pulses in repetitive blips an extracted current density over 90 % ITER target value by improving electron symmetry. In roughly 67...
Abstract Negative ion sources for neutral beam injection rely on surface production of negative ions a caesiated low work-function (plasma grid). To maintain the work function in long pulses (one hour) and desired source performance (extracted H - /D limited co-extracted electrons), Cs needs to be constantly delivered onto plasma grid. The CsFlow3D code was applied RF driven ELISE simulate evaporation plasma-assisted redistribution Cs. flux stability is investigated consecutive one hour...
Abstract The BATMAN Upgrade (BUG) test facility at IPP is contributing to the development of RF-driven H - sources towards ITER neutral beam injection and beyond. BUG equipped with an 1/8 size NBI ion source thus highly flexible for setup changes or diagnostic access. present strategy aligned along two paths: (i) continuing be upgraded upgrading long pulse operation (up 1 hour, both in D) identify measures stabilization pulses. For pulses > 100 s a cooling plasma grid (first extraction...