Plasma Physics

Research Topics

Turbulence in magnetised plasmas
Fisica dei plasmi

R. Barni, C. Riccardi

Research concerns turbulence, in particular the different topics which could be studied experimentally in laboratory plasmas. Turbulence is a phenomenon, not well understood yet, concerning several fields of physics. In plasmas, turbulence represents a substantial limitation to control and confinement of plasmas, in particular magnetised plasmas aimed to thermonuclear controlled fusion applications. Experiments are performed on the toroidal device Thorello (a simple magnetised torus, SMT) at the PlasmaPrometeo Center of the Department. Research is performed also abroad within collaborations with the Auroral Observatory (University of Tromso - Norway, Observatory website) and the Centre pour le Physique des Interactions Ionique et Moleculaires PIIM (CNRS - Marseille, PIIM website), with the Istituto di Fisica del Plasma IFP (CNR - Milano, IFP website) and with Enea (ENEA - Frascati, ENEA website).
Recent results concern the numerical analysis of plasma fluctuation statistical properties, the study of diffusion and anomalous transport mechanism, the search and characterization of coherent structures, the investigation of wave-plasma interactions in magnetized plasmas. Linked to this research field there are activities like the development of magnetized plasma diagnostics with electrostatic and optical probes. The Center hosts foreign researchers and PhD students for research fellowships as visiting at the Department (Dr. E. Ghorbanpour, Rasht, Iran; Dr. T. Abbaszadeh, Tabriz, Iran, PhD A. Prince, Gujarat, India).

Plasma Applications

R. Barni, C. Riccardi

Applied research on plasma processing is perfromed at the PlasmaPrometeo Center. Research concerns the project and the development of plasma devices for the surface modification of materials, the treatment of gas mixtures and for the production of energy. Activities concern studies and optimizations of different plasma processing, even within contracts with industrial companies. Linked to this research field, there are activities aimed to the development of diagnostics for radiofrequency plasmas with electrostatic probes, the optical emission spectroscopy and of numerical codes for the simulation of the chemical kinetics in plasmas. At the Center laboratories for the analysis of plasma treated materials have been opened. The first has an atomic force microscopy (AFM) which could study the surface morphology at the nanometer scale. With similar tecniques it is possible to measure several surface parameters such as electrical conductivity, elasticity and hardness. The second laboratory concerns optics, with a laser system for dusty plasma diagnostics through interferometric methods.

Fast ion physics in thermonuclear plasmas

M. Nocente, G. Gorini

Suprathermal ions, such as those born from the fusion reactions or generated by the auxiliary heating systems, play a key role for plasma heating in magnetically confinement devices. For instance, fast ions can lead to magnetohydrodynamic instabilities that, under some circumstances, in turn lead to the loss of a significant fraction of the energetic ions themselves.
Our group is concerned with the experimental study of the energetic ions by means of nuclear radiation measurements, predominantly neutron and gamma-ray spectroscopy in tokamak plasmas. The activity comprises the design, participation and coordination of dedicated experiments, in particular at the Joint European Torus (Culham, UK), as well as data taking and their detailed analysis. An important aspect is the direct validation of plasma models, which is made possible by the development of codes to predict the emission of nuclear radiation from tokamak plasmas starting from the model and its direct comparison to spectroscopy data.Our activities are in collaboration with the Plasma Physics Institute of the National Research Council (contact person: Dr. Marco Tardocchi).

Runaway electron physics in thermonuclear plasmas

M. Nocente, G. Gorini

When a sudden loss of the magnetic confinement occurs (disruption), due to the large induced electromotive forces, fusion plasmas can generate beams of unconfined MeV range electrons (runaways), which impact the machine first wall and can threaten its integrity. Our group studies the experimental dynamics of the generation, development and possible dissipation of runaway electron beams by means of time revolved measurements of soft and hard X-rays born by runaway bremsstrahlung. The activity is carried out both on large size (for example, the Joint European Torus in Culham, UK) and on medium size tokamaks, in the framework of European and international collaborations. In particular, we participate in the main international experiments on disruption mitigation and we use soft and hard X ray spectroscopy data to validate models on the runaway electron dynamics, by means of model based simulations of the emission and direct comparison with data.
Our activities are in collaboration with the Plasma Physics Institute of the National Research Council (contact person: Dr. Marco Tardocchi).

 

Development of detectors for neutron, gamma and X-ray spectroscopy for fusion plasmas, spallation sources and fusion technologies

G. Croci, M. Nocente, G. Gorini

Neutron, gamma and X ray spectroscopy of fusion plasmas imply the development of detectors that meet the demanding temporal and energy response requirements needed for measurements in a tokamak environment. Our group is concerned with the design, development and characterization of neutron, gamma and X-ray spectrometers of different dimensions (compact and non compact) and based on solid and liquid detectors (mostly, scintillators) or gas devices. The instruments are built and tested in our laboratories and later installed at the main European and international thermonuclear fusion facilities. Starting from this experience, we also develop neutron and gamma-ray spectrometers of interest for spallation sources and fusion technologies.
Our activities are in collaboration with the Plasma Physics Institute of the National Research Council (contact person: Dr. Marco Tardocchi).
 

Neutron spectroscopy applied to the study of cultural heritage artefacts
Neutron spectroscopy applied to the study of cultural heritage artefacts

D. Di Martino, G. Gorini

Starting from the experience in plasma neutron spectroscopy, our group is involved in the development of new non-destructive neutron-based techniques for the study of cultural heritage artefacts. For example, neutron resonances have been used for the 3d elemental mapping of archaeological specimens. We get access to many European facilities to perform experiments by neutron diffraction (to analyze the mineralogical phases), by neutron resonant capture analysis (to obtain elemental information), by prompt gamma activation analysis (to get the materials composition), and by neutron imaging (to study the inner morphology of the objects).
Recently, we studied musical instruments, artefacts from the Museo Egizio di Torino, the Chiaravalle Cross and some gemmological samples.
Our activities are in collaboration with the Plasma Physics Institute of the National Research Council (contact person: Dr. Enrico Perelli Cippo).