World Congress on Plasma Chemistry and Plasma Processing September 21-22, 2020 Milan, Italy

Artificial plasmas are generated by the application of electric or magnetic fields through a gas. Plasma generated in a laboratory setting and for industrial use can be generally categorized by: The type of power source used to generate the plasma

• Arcs produced by Tesla coils
• Plasmas used in semiconductor device fabrication including reactive-ion etching, sputtering, surface cleaning and plasma-enhanced chemical vapour deposition
• Laser-produced plasmas (LPP), found when high power lasers interact with materials.
• Inductively coupled plasmas (ICP), formed typically in argon gas for optical emission spectroscopy or mass spectrometry

Plasma processing is a plasma-based material processing technology that aims at modifying the chemical and physical properties of a surface. Plasma processing techniques include:

• Plasma activation
• Plasma ashing
• Plasma cleaning
• Plasma electrolytic oxidation
• Plasma etching
• Plasma functionalization
• Plasma polymerization
• Corona treatment
• Plasma modification

Plasma diagnostics are a pool of methods, instruments, and experimental techniques used to measure properties of plasma, such as plasma components density, distribution function over energy (temperature), their spatial profiles and dynamics, which enable to derive plasma parameters. Plasma diagnostic techniques are also used to observe physical processes that reveal parameters that characterize plasma. These parameters include spatial and temporal distributions of constituent particle densities and temperatures and localized magnitudes of electric and magnetic fields. The techniques used include those that have applications in other areas of science and those that have been developed for their unique applications to plasmas.

The number of industrial applications of plasma-based systems for processing of materials and for surface modification is extensive, and many industries are impacted. Some of these processes and corresponding applications include:

• Plasma-controlled anisotropic etching in fabrication of microelectronic chips
• Plasma deposition of silicon nitride for surface passivation and insulation
• Surface oxidation used in fabrication of silicon-based microelectronic circuits
• Plasma-enhanced chemical vapour deposition of amorphous silicon films used in solar cells
• Plasma-surface treatment for improved film adhesion to polymer surfaces
• Plasma nitriding, which is used to harden the surface of steel;
• Plasma-enhanced chemical vapour deposition and thermal plasma chemical vapour deposition of diamond thin films
• Plasma spray deposition of ceramic or metal alloy coatings used for protection against wear or corrosion in aircraft and automotive engines

• Lightning
• The magnetosphere contains plasma in the Earth's surrounding space environment
• The ionosphere
• The plasma sphere
• The polar aurorae
• The polar wind, a plasma fountain
• Upper-atmospheric lightning (e.g. Blue jets, Blue starters, Gigantic jets, ELVES)

Inertial confinement fusion (ICF) is a type of fusion energy research that attempts to initiate nuclear fusion reactions by heating and compressing a fuel target, typically in the form of a pellet that most often contains a mixture of deuterium and tritium. Typical fuel pellets are about the size of a pinhead and contain around 10 milligrams of fuel.

Plasma physics is the study of a state of matter comprising charged particles. Plasmas are usually created by heating a gas until the electrons become detached from their parent atom or molecule. This so-called ionization can also be achieved using high-power laser light or microwaves. Plasmas are found naturally in stars and in space.

Lightning is an example of plasma present at Earth's surface. Typically, lightning discharges 30,000 amperes at up to 100 million volts, and emits light, radio waves, X-rays and even gamma rays. Plasma temperatures in lightning can approach 28,000 K and electron densities may exceed 1024 m−3.

Magnetic confinement fusion is an approach to generate thermonuclear fusion power that uses magnetic fields to confine fusion fuel in the form of plasma. Magnetic confinement is one of two major branches of fusion energy research, along with inertial confinement fusion. The magnetic approach began in the 1940s and absorbed the majority of subsequent development.

• Magnetic mirrors
• Toroidal machines

Space physics is the study of plasmas as they arise naturally in the Earth's upper atmosphere. It includes heliophysics which includes the solar physics of the Sun: the solar wind, planetary magnetospheres and ionospheres, cosmic rays. It is an essential part of the study of space weather and has important consequences not only to understand the universe, but also to practical everyday life, and also includes the process of communications and weather satellites. Space physics uses measurements from high altitude rockets and spacecraft.

• Mathematics and physics analysis of large data sets
• Problems in the information, science, and technology portfolio
• Computational neuroscience
• Computational biology and biophysics
• Network analysis
• Mathematical modeling applied to emergent Threat Reduction and Energy Security problems
• Plasma physics applied to emergent Energy Security problems
• Software engineering
• Algorithm development for scalable scientific computing on novel parallel architecture

Plasma processing is a plasma-based material processing technology that aims at modifying the chemical and physical properties of a surface. Plasma processing techniques include: Plasma activation, Plasma etching. Plasma processing of materials is also a processing technology which is used in aerospace, automotive, steel, biomedical, and toxic waste management industries it is also been utilized increasingly in the emerging technologies of diamond film and superconducting film growth.

Since plasmas are very good electrical conductors, electric potentials play an important role. The average potential in the space between charged particles, independent of how it can be measured, is called the "plasma potential", or the "space potential". If an electrode is inserted into plasma, its potential will generally lie considerably below the plasma potential due to what is termed a Debye sheath. The good electrical conductivity of plasmas makes their electric fields very small. This result in the important concept of "quasineutrality", which says the density of negative charges, is approximately equal to the density of positive charges over large volumes of the plasma, but on the scale of the Debye length there can be charge imbalance. In the special case that double layers are formed, the charge separation can extend some tens of Debye lengths.

Thermal plasmas have electrons and the heavy particles at the same temperature, i.e. they are in thermal equilibrium with each other.

Non-thermal plasmas on the other hand are non-equilibrium ionized gases, with two temperatures: ions and neutrals stay at a low temperature, whereas electrons are much hotter. A kind of common non-thermal plasma is the mercury vapour gas within a fluorescent lamp, where the "electrons gas" reaches a temperature of 10,000 kelvins while the rest of the gas stays barely above room temperature, so the bulb can even be touched with hands while operating.

Plasma treatment alters the surface wetting properties, which, in the end, can augment the functionality and biocompatibility of biomaterial surfaces. Plasma presents oxygen-containing functional groups to improve surface hydrophilicity of biomaterials, without an impact on their main material properties. This improves the bonding properties of later coatings or absorption of other functional groups. Additionally, oxygen plasma has the extra advantage of both cleaning and sterilizing biomaterial surfaces in laboratory research environments at once.

"Liquid and crystalline phases can be formed in so-called complex plasmas - plasmas enriched with solid particles in the Nano- to micrometre range. The particles absorb electrons and ions and charge negatively up to a few volts. Due to their high mass compared to that of electrons and ions the particles dominate the processes in the plasma and can be observed on the most fundamental - the kinetic level. Through the strong Coulomb interaction between the particles it is possible that the particle clouds form fluid and crystalline structures. The latter is called 'plasma crystal'.

Low-energy plasmas occupy a large portion of the density-temperature plane, with electron densities ranging from 105 to 1028 m-3 and electron temperatures ranging from 100 to 105 Kelvin. Two regimes in the density-temperature plane are characteristic of plasmas used in plasma processing. One of these includes glow discharges, in which the temperatures of electrons and heavy particles are widely disparate. The second includes thermal plasmas, in which electrons and heavy particles are in approximate thermal equilibrium. These plasmas are classical in nature in that the thermal kinetic energy is large in comparison to the average Coulomb interaction energy. Thus, charged particles usually interact weakly with each other, and electron collisions are usually most frequent with neutral atoms and molecules.

Atmospheric-pressure plasma (normal pressure plasma) is plasma in which the pressure approximately matches that of the surrounding atmosphere – the so-called normal pressure. Atmospheric-pressure plasmas have prominent technical significance because in contrast with low-pressure plasma or high-pressure plasma no reaction vessel is needed to ensure the maintenance of a pressure level differing from atmospheric pressure. Accordingly, depending on the principle of generation, these plasmas can be employed directly in the production line. The need for cost-intensive chambers for producing a partial vacuum as used in low-pressure plasma technology is eliminated. Various forms of excitation are distinguished:

• AC (alternating current) excitation
• DC (direct current) and low-frequency excitation
• Excitation by means of radio waves
• Microwave excitation

The number of potential applications of non-equilibrium atmospheric pressure discharges in biology and medicine has grown and activity in this direction lead to the formation of a new field in plasma chemistry titled 'Plasma Medicine'. Some examples of medical applications of plasma are the use of plasma in the treatment of dental cavities, sterilization of various surfaces, treatment of skin diseases, delicate surgeries and many other applications. It is now clear that these plasmas can have not only physical (e.g. burning the tissue) but also medically relevant therapeutic effects; plasmas can trigger a complex sequence of biological responses in tissues and cells. The development of actual commercial tools that will enter the hospital, and in finding novel and perhaps even unexpected uses of these plasmas, an understanding of the mechanisms of interaction of non-equilibrium gas discharges with living organisms, tissues and cells becomes essential.

• Treatment of Air Pollutants
• Conventional NTP Reactors
• Hybrid NTP/WET Process Systems
• Treatment of Polluted Waters
• Solid Waste Treatment

Plasma processing represents an attractive and versatile option for the fabrication of low-dimensional nanomaterials, whose chemical and physical properties can be conveniently tailored for the development of advanced technologies. In particular, Plasma Enhanced-Chemical Vapour Deposition (PE-CVD) is an appealing route to multi-functional oxide Nano architectures under relatively mild conditions, owing to the unique features and activation mechanisms of non-equilibrium plasmas. In this context, the potential of plasma-assisted fabrication in advanced Nano system development is discussed. Nano materials are used in a variety of, manufacturing processes, products and healthcare including paints, filters, and insulation and lubricant additives. In healthcare Nanozymes are nanomaterials with enzyme-like characteristics. They are an emerging type of artificial enzyme, which have been used for wide applications in such as biosensing, bioimaging, tumour diagnosis, antibiofouling and more. In paints nanomaterials are used to improve UV protection and improve ease of cleaning.

• Plasma Blasting Hazardous Waste
• Plasma Particle Accelerator Afterburner
• Plasma Scalpels
• Antimatter Annihilation Plasma
• Plasma coatings
• Plasma surface activation