As comprehensively reviewed in [1], enormous volume of work has been carried out in understanding and control of various MHD instabilities, in particular in the Tokamak configurations and significant progress has been achieved. Yet, unresolved issues remain, where the MHD description is expected to play important contributions. We here present a survey of our activity focussed to the...
The projects of neutron sources based on nuclear fusion is becoming an important argument for the strategic positioning of the road-map of fusion realization worldwide. In this context, the paper presents a NEW innovative conceptual study of a neutron source based on a spherical tokamak(ST). The plasma scenario chosen for the ST is non-thermal fusion ( hot ion mode) , extensively used on...
Understanding the mechanisms that govern the turbulent dynamics in tokamak devices is of primary interest for achieving a net production of energy from nuclear fusion processes.
In this work, we investigate the turbulent transport of blob-like structures in the Scrape-Off Layer by means of numerical simulations based on the reduced Braginskii equations in a simplified geometry. We derive a...
In modern magnetic fusion devices plasma temperatures of several keV are obtained, so that relativistic effects may play an important role on the electron kinetics. We report here on the development of a new 2.5D fully relativistic, bounce-averaged Fokker-Planck code, suitable for the simulation of the radio frequency heating in both tokamaks and stellarators.
The present code represents a...
Mitigating the heat load to the divertor is a key challenge for future fusion reactors. Current material limits constrain the allowable heat flux to below 10 MW/m², requiring a significant fraction of the power exhausted from the core plasma to be radiated to maintain acceptable conditions at the divertor. In next-step devices, such as ITER and DEMO, sustained operation without damage demands...
Il trasporto di particelle ed energia in un tokamak è prevalentemente di natura turbolenta e costituisce un aspetto cruciale per il confinamento del plasma. La sua comprensione risulta quindi necessaria per la pianificazione dei futuri reattori e per la massimizzazione della performance. Da un punto di vista empirico, la turbolenza si manifesta tramite coefficenti di trasporto cosiddetti...
In magnetized plasmas, there are many dynamical processes that affect the ion velocity distribution function, both in laboratory and astrophysical environments. Measurements of this quantity can give useful insights for the study of phenomena such as magnetic reconnection, ion heating and acceleration, and turbulence activity. For this purpose, we designed a new diagnostic system that...
The EuPRAXIA (European Plasma Research Accelerator with
eXcellence In Applications) is one of the projects on the European Strategy Forum on Research Infrastructures (ESFRI) Roadmap of 2021 that aims to develop the first worldwide plasma acceleration user facility. A particle-beam-driven scheme with driver and witness electron bunches will deliver electron bunches with an energy range of GeV...
When a high-intensity laser interacts with matter, it creates a plasma, thus emitting particles and generating strong electromagnetic (EM) radiation. We focus for this study on the emitted EM fields ranging from MHz to THz, known as electromagnetic pulses (EMPs). These EMPs, originating from various sources in laser-matter interactions [1], can reach peak intensities of the MV/m order, posing...
In a tokamak plasma, impurities can diffuse depending on their atomic mass. One of the main (unwanted) source of impurities is erosion or sputtering of the first wall and of the divertor. The presence of different kind of impurities can modify the plasma dynamics, trigger instabilities, and dissipate energy through radiation.
In the past years, JET-ILW (ILW is for ITER-Like-Wall composed by a...
In tokamak fusion devices, Plasma-Wall Interaction (PWI) represents one of the main concerns for future reactors. Indeed, such phenomena lead to the erosion of Plasma Facing Components (PFCs), resulting in the transport of eroded particles into the plasma and their subsequent redeposition. These processes significantly affect plasma confinement performance, as well as the lifetime and...
Plasma wakefield acceleration (PWFA) represents one of the most promising routes toward compact high-gradient accelerators. While its modeling has long relied on the cold-plasma approximation, several physical and technological developments now call for the inclusion of finite temperature effects. Thermal pressure becomes relevant near the wavebreaking threshold, where it regularizes singular...
One of the main challenges in magnetically confined fusion research is the development of plasma-facing materials able to withstand the harsh environment of long-term plasma exposure. Linear plasma devices are widely used to address this issue. GyM [1] is one such device, capable of generating steady-state plasmas with electron temperatures up to 15 eV, densities in the range of...
In magnetic confinement fusion, tokamak plasmas with negative triangularity (NT) have emerged as a promising alternative to H-mode operation scenarios, achieving high confinement while remaining in L-mode, thus inherently free of edge-localized modes [1]. Recent experiments in Tokamak a Configuration Variable (TCV) have shown that NT plasmas feature more challenging access to divertor...
The interaction of high-intensity laser pulses with matter generates a wide range of physical phenomena, including particle acceleration and emission of pulsed electromagnetic radiation ranging from ionizing (γ, X, UV) to non-ionizing frequencies. Among these emissions, Electromagnetic Pulses (EMPs) extend from the MHz to the THz range [1] and can reach field strengths of several MV/m at...
Particle-in-cell (PIC) simulations are a well-established tool to study and predict the outcomes of a Laser Plasma Accelerator experiment, but the results are often hindered by the initialization of highly idealized laser profiles. In this work, we present the development of a Laser Pulse reconstructor For Particle In Cell simulations (LP4PIC), a Python package to retrieve experimental laser...
The RFX-mod device is a toroidal device for the magnetic confinement of fusion relevant plasmas, which is presently being upgraded and is planned to restart operation as RFX-mod2 with a modified and improved magnetic boundary. Thanks to the flexibility of its power supply and advanced feedback control systems it can be operated in a variety of configurations, mainly the tokamak and the...
The Plasma Unit of the Institute of Complex Systems of the CNR at the Politecnico di Torino focuses on the theoretical and numerical analysis of magnetic reconnection processes in plasmas of interest for both space and fusion applications. In particular, we study the fundamental processes that govern the interaction between magnetic reconnection and fluid turbulence [1,2], the instability of...
Understanding plasma–wall interaction is a key step on the path towards the exploitation of nuclear fusion energy [1]. The erosion of plasma-facing components (PFCs) can shorten their lifetime, while the eroded material — typically tungsten (W), owing to its favourable plasma-interaction properties — may contaminate the confined plasma, degrading the performance through fuel dilution and...
Laser-Induced Breakdown Spectroscopy (LIBS) is a promising diagnostic technique for monitoring PFCs during and after plasma exposure, enabling the assessment of elemental and isotopic composition through optical emission spectroscopy. For quantitative depth profiling and fuel retention studies, accurate knowledge of the ablation rate and thermal effects induced by a single laser pulse is...
Axisymmetric modes (toroidal mode n=0) are considered to play an influential role in the stability of future tokamak fusion plasmas where the large presence of fusion alpha particles can potentially drive these modes [1]. Among them, two possible ones are the well-known GAE (Global Alfven Eigenmode), and the newly emerged VDOM (Vertical Displacement Oscillatory Modes) [2]. Being global in...
Laser-accelerated electron beams, in the so-called Very High-Energy Electron (VHEE) energy range, are of great interest for biomedical applications, particularly for developing compact accelerators for FLASH radiotherapy. Reliable real-time dose information is essential for radiobiology experiments using such laser-driven sources. We present an online dose-monitoring method based on an...
We propose and test a multi-step preliminary analytical procedure that tailors the initial
density fn0 of a cold diluted collisionless plasma to a very short and intense plane-wave
laser pulse travelling in the z direction, so as to maximize the early laser wakefield acceleration
(LWFA) of bunches of plasma electrons self-injected in the plasma wave (PW) by the
first wave-breaking (WB) at...
This work provides an overview of the progress achieved so far in the electromagnetic simulation of plasma instability phenomena in tokamaks, focusing on the Divertor Tokamak Test (DTT). The main aim is to provide a concise summary of the current strategies for disruption mitigation, focusing on Shattered Pellet Injection (SPI), seen as the primary disruption mitigation method during the...
The Divertor Tokamak Test (DTT) facility is a large experiment under design and construction at the ENEA Research Centre in Frascati, Italy. Its main goal is to assess alternative solutions for the heat and power exhaust problem in future fusion plants [1]. To this end, different configurations will be tested, and safe operation must be ensured in all of them.
One of the major challenges in...
The Plasma Control System (PCS) is an essential component of any tokamak, responsible for the real-time management of the plasma to ensure stable operation and optimal performance during fusion experiments. It works in conjunction with other subsystems to monitor and control key parameters during a plasma discharge like the plasma shape, position, density, and temperature.
The DTT PCS...
The Tuscia Research University Small Tokamak (TRUST) is a compact university-scale device currently under design at Università degli Studi della Tuscia. Conceived as a flexible and cost-effective platform, TRUST supports education, technology development, and physics studies of relevance to next-generation fusion devices. The conceptual design foresees a baseline single-null configuration with...
Abstract:
During the DTE2 and DTE3 JET campaigns, efforts were made to develop a high-current baseline scenario [1]. Baseline plasmas were affected by impurities (primarily beryllium Be and tungsten W), which were localised on the low-field side of the device. Tomograms derived from bolometric measurements highlighted regions of high radiated emissivity at the periphery of the plasma....
The research activity of the Intense Laser Irradiation Laboratory (ILIL) at Istituto
Nazionale di Ottica in Pisa is focused on fundamental studies of high-intensity laser
interaction with matter and their applications. The Laboratory participates to the
European Infrastructures EuPRAXIA, ELI and HiPER+ and is a member of the
Laserlab-Europe AISBL. Fundamental studies include plasma...
The intense-laser interaction with low-density nanostructured materials has received increased interest owing to the peculiar regime they enable [1]. This interaction regime, characterised by increased coupling between the laser radiation and the plasma, enables a more efficient heating of the plasma species without any change in the laser parameters, both at ultra-high intensities...
Electron beams produced via Laser Wakefield Acceleration are notoriously known for their pointing instability, which makes the retrieval of the energy spectrum via magnetic spectrometers prone to energy miscalculations. Here, we demonstrate an improved scheme of a previously published spectrometer employing two scintillating screens and a magnetic dipole in between. The first screen provides...
Forward and inverse problems play a fundamental role in many areas of plasma physics and nuclear fusion, including plasma performance prediction, instability evolution analysis, transport modelling, equilibrium reconstruction, and tomography. Typically, forward numerical models are developed under specific assumptions, and their parameters are iteratively adjusted to match experimental data....
Developing open, transparent, and transferable knowledge frameworks is essential for advancing plasma physics research and supporting both theoretical and experimental studies. In this context, we have developed TokaLab: an open-access virtual tokamak designed for education and research. This repository aims to foster learning, collaboration, and the adoption of the FAIR principles (Findable,...
Plasma–material interactions are a key challenge for magnetic confinement fusion and are widely investigated in linear plasma devices. The GyM [1] linear device currently operates at plasma densities of $10^{15}–10^{17}\text{m}^{-3}$, electron temperatures below 15 eV, and ion fluxes up to $10^{21} \text{m}^{-2} \text{s}^{-1}$, representative of tokamak main chamber conditions.
To reach...
In the framework of magnetic reconnection studies, and in collaboration with EUROfusion partners, we study how the presence of a large magnetic island, like the ones due to a (neoclassical) tearing mode in a tokamak, changes the transport in radial direction (core to edge and vice versa) [1]. The general purpose is to study the interplay between such an island and the accumulation of tungsten...
Recent progress on the theory, numerical simulations, and experimental observations of Vertical Displacement Oscillatory Modes (VDOM) in tokamak experiments is reported. VDOM are axisymmetric modes (toroidal mode number n=0) driven unstable by energetic particles and can have an impact on plasma disruptions, plasma edge stability and confinement. They are a candidate to explain...
