78464 - Plasma Engineering M

Learning outcomes

At the end of the course, students can understand the main aspects of plasma physics and the behaviour of plasmas under different operating conditions. Some technologies based on the use of plasmas are discussed in detail: - plasma treatment of surfaces (plasma etching, deposition, implantation and sputtering); - electroplasmadynamic and magnetoplasmadynamic interactions and their applications; - Main aspects of thermonuclear fusion with magnetic confinement. Therefore, students at the end of the course can operate on advanced technologies used in industry and in the field of research.

Course contents

lements of plasma physics:

Definition of Plasma. Characteristic quantities of a plasma: Debye length, natural frequency of the plasma

Motion of charged particles: motion of a charged particle in electromagnetic fields, magnetic moment of a charged particle and adiabatic invariants, magnetic mirrors.

Radiative-collisional processes: fundamental particles of a plasma, cross sections and reaction rates, mass velocities of a plasma, conduction and convection electric currents, elastic collisions, Coulomb collisions and non-elastic collisions in ionized gases.

Radiative processes: bound-bound radiation, spontaneous emission, forced emission and absorption, line widening, bound-free radiation and free-free radiation.

Statistical behavior of plasmas: Vlasov equation. Maxwellian velocity distribution, Boltzmann relations, Saha relation and Plank relation, detailed balance principle, equilibrium regimes. Maxwell-Boltzmann equation. Fokker-Plank equation.

Collective phenomena: Coulomb's shielded potential and sheath effect, electrical conductivity in an ionized gas, Hall parameter, generalized Ohm's law.

Plasma models: MHD model, MHD approximation; drift-diffusion model; particle models (Particle in Cell)

Magneto fluid dynamics:

diffusion and convective regimes, magnetic Reynolds number and interaction parameter. Applications: MHD energy conversion, MHD interactions in hypersonic flows in spacecraft reentry.

Controlled thermonuclear fusion:

Physical principle of fusion and main characteristics of fusion plasmas: main fusion reactions, Coulomb barrier and reaction probability, energy balances, break-even and ignition criteria, Lawson's criterion, magnetic plasma confinement, confinement surfaces and diamagnetic properties of the plasma, linear configurations, z-pinch and Bennet's equation, stabilized z-pinch, toroidal configurations, calculation of the equilibrium magnetic field, safety factor and ergodicity of the magnetic system, types of toroidal configurations, tokamak, reversed field pinch and stellarator, instability in fusion plasmas, MHD instability in linear and toroidal configurations, stabilization of toroidal configurations, heating of the plasma, engineering aspects of a tokamak machine.

Electric discharges:

Characteristics of the discharge in a gas: energy and active species, equilibrium and non-equilibrium, black discharge, Townsend discharge, breakdown, glow discharge and arc discharge. High frequency discharges: inductive, capacitive and microwave discharges. The barrier discharge (DBD). Electro-fluid-dynamic interaction (EHD) in barrier discharges. Applications of the EHD effect in aeronautics.

Plasma technologies:

Plasma and plasma jet torches: fundamental characteristics and construction aspects of the main plasma generators used in the technique: plasma engraving, plasma deposit, plasma system, erosion and plasma corrosion. Some technological applications.

Aerospace applications: space propulsion, rocket equation, electric propulsion, resistorjet, ion thrusters, Hall thrusters, MPD thrusters.

Readings/Bibliography

The complete series of slides projected during the lessons is available on Virtuale.

The texts recommended for consultation and details are:

• J.D. Jackson, “Classical Electrodynamics”, John Wiley and Sons, New York, 1975
• J.L. Shohet, “The Plasma State”, Academic Press, New York, 1971
• L. Spitzer, “Physics of Fully Ionized Gases”, Interscieces, 1962
• R.J. Rosa, “Magnetohydrodynamic Energy Conversion”, McGraw Hill, 1968
• M. Mitchner and C.H. Kruger, “Partially Ionized Gases”, John Wiley and Sons, New York, 1973
  
• W.M. Stacey, “Fusion Plasma Analysis”, John Wiley and Sons, New York, 1981

Teaching methods

The course takes place on the second cycle of the second year of the master degree course in "Ingegneria dell'Energia Elettrica", and consists of 6 credits corresponding to 60 hours of lectures, during which the teacher will explain in classroom the topics covered in the program. During the course, the teacher will assign students homework to verify the learning of the topics covered in class.

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Students with specific learning disorders (SLD) or temporary/permanent disabilities:

We recommend contacting the University Office responsible for support services in a timely manner (https://site.unibo.it/studenti-con-disabilita-e-dsa/it) [https://site.unibo.it/studenti-con-disabilita-e-dsa/it):] ). The office will evaluate the students' needs and, where appropriate, propose possible accommodations. These must in any case be submitted for approval at least 15 days in advance to the course instructor, who will assess their suitability also in relation to the learning objectives of the course.

Assessment methods

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The examination is designed to assess the student's acquisition of the fundamental knowledge of plasma science and technology. Students may choose one of the following examination formats.

Option 1: Oral Examination

During the oral examination, students are expected to demonstrate their understanding of the fundamental concepts of the course and their ability to apply the acquired knowledge to practical problems. They will also be asked to discuss selected topics covered during the course. The discussion is intended to assess the student's overall understanding of the subject, their command of the appropriate technical terminology, and their ability to analyze and synthesize the course material.

Students are also required to present a brief report on the activities assigned during the course and discuss the results obtained.

The final grade will be based on the extent to which the above learning objectives have been achieved.

Option 2: Midterm Written Examinations

The examination may also be completed through continuous assessment. During the course, two or more midterm tests will be scheduled, each covering the topics taught during the corresponding period. Each test will consist of a written assessment based on a set of open-ended and/or multiple-choice questions designed to evaluate the students' understanding of the material covered up to that point. The specific format of the midterm tests and the assessment criteria will be explained by the instructor at the beginning of the course.

The final grade will be determined on the basis of the scores obtained in the midterm tests and the outcome of a final oral examination, which will focus on the discussion of the reports related to the activities assigned by the instructor during the course.

Teaching tools

The slides projected during the lessons are available on the Virtuale platform. 

Matlab functions developed during the tutorials will be made available on Virtuale.

Office hours

See the website of Andrea Cristofolini