Plasma Physics

Research Topics

Basic studies on the physics and chemistry of low-temperature plasmas
Fisica dei plasmi

C. Riccardi, E. Martines

This research area concerns the development of new plasma sources, both at low pressure and at atmospheric pressure, the development and improvement of diagnostic techniques and the study of the physical-chemical phenomena occurring in low-temperature plasmas. In particular, studies are currently underway on the production of ozone and nitrogen oxides in dielectric barrier surface discharges in air, on the initiation and maintenance of radiofrequency plasmas, on the detection of chemical species produced by plasmas through the use of Fourier transform infrared spectroscopy, on the characterization of plasmas by means of advanced techniques such as mass spectroscopy and fast cameras.

Collaborations: University of Milano, EPFL-Lausanne, Consorzo RFX, University of Bologna

Applications of plasmas to material science

C. Riccardi, R. Barni, E. Martines

Applied research activities in the field of materials science take place at the PlasmaPrometeo Centre. Research focuses on the design and manufacture of plasma devices for the surface treatment of materials, gas mixtures and for energy production. They also cover the study and optimization of different plasma treatment processes, also within the framework of contracts with industries. Also linked to this research line are activities concerning the development of diagnostic devices for radiofrequency plasmas using electrostatic probes and optical emission spectroscopy, and the development of numerical simulation codes for the chemical kinetics of plasmas. The Centre also has laboratories for the characterization of materials treated with plasma processes. The first is equipped with an atomic force microscope (AFM) capable of studying surface morphology at the nanoscale. Other surface parameters such as electrical conductivity, elasticity and hardness can be measured using similar techniques. The second laboratory is dedicated to optics, with a laser system for diagnosing plasmas containing nanoparticles using optical interferometry methods.

Collaborations: University of Milano

Biomedical plasma applications

E. Martines, C. Riccardi

An area of application for plasmas produced at atmospheric pressure that has recently met with great interest is that of applications in the biomedical sector ("plasma medicine"). The activities currently underway concern the application of plasma to disinfection of living tissues, inanimate surfaces and air flows, with particular regard to the inactivation of resistant pathogens and the emergence of resistance to the action of plasma, and the study of the effects of plasma on the cellular processes of eukaryotic cells, with implications for the stimulation of wound healing and the possible anti-tumor effect. The studies make use of advanced diagnostic techniques such as transmission electron microscopy and atomic force microscopy.

Collaborations: University of Milano, EPFL-Lausanne, Consorzo RFX, University of Bologna, University of Padova

Turbulence in magnetized plasmas

R. Barni, C. Riccardi

The activities concern the different aspects of the phenomenon of turbulence that can be studied experimentally in laboratory plasmas. Turbulence represents a phenomenon, still not perfectly understood, that occurs in very different fields of physics. In plasmas it represents also a substantial limitation to the control and confinement of plasmas, in particular the magnetized ones of interest in applications for the exploitation of thermonuclear fusion. The experiments are carried out on the Thorello toroidal machine with simple magnetized plasma located at the PlasmaPrometeo Center of the Department.

Fast ion physics in thermonuclear plasmas

M. Nocente, G. Gorini, M. Cavedon

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, M. Cavedon

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).

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