Plasma physics laboratory 1

A.Y. 2020/2021
6
Max ECTS
57
Overall hours
SSD
FIS/03
Language
Italian
Learning objectives
The course is meant to provided experimental skills applied to the investigation of plasmas (and specifically nonneutral plasmas) and charged particle beams.
Expected learning outcomes
After attending the course, the student will possess the following set of knowledge and skills:
- Basics of the theory of plasmas/nonneutral plasmas
- Basic notions about the interest of experimental nonneutral plasma physics
- Basics of vacuum techniques
- Knowledge of the theory and practice of operation of experimental plasma machines (Penning-Malmberg traps)
- Formulation and design of experiments and experimental routines
- Performance of experiments with research-level instrumentation
- Theory and practice of data acquisition and analysis: electrostatic signals, Fourier analysis
- Theory and practice of data acquisition and analysis: phosphor screen-CCD camera images, image denoising and analysis
- Preparation of experimental reports, critical evaluation of results and experimental limitations.
Course syllabus and organization

Single session

Responsible
Lesson period
Second semester
If severe limitations arise due to the COVID-19 emergency, the course may switch to remote delivery methods. In such case, lectures will be delivered sinchronously according to the official schedule of the Physics Course and using the virtual classrooms system of the Physics Department implemented through the Zoom platform, thus enabling real-time interactions between students and teacher. Suitable ways to participate in the conception, performance and discussion of the experiments will be devised and the contents may be adjusted to suit the situation. Student reception and oral examinations will also be held remotely in a virtual room of the Physics Department.
Course syllabus
LECTURES:
Elements of quasi-neutral plasma physics. Introduction to nonneutral plasmas. Diocotron modes, derivation of the eigenvalue equation. Ion-induced and resistive diocotron instability. Plasma manipulation methods: Feedback damping, autoresonance. Temperature and diffusion of a trapped plasma.

Harmonic signal analysis: Fourier series, continuous and discrete Fourier transform, sampling theorem, Nyquist limit and aliasing.

Description of the experimental set-up (Penning-Malmberg trap), diagnostic tools and instrumentation in the laboratory.

Elements of vacuum techniques and electronic measurements (electrostatic signal amplifiers; transimpedance).

Introduction to data analysis: Methods, protocols, creation of analysis programs and result visualization in signal and image processing.

EXPERIMENTS (the students will perform some of the experiments listed here):

Electrostatic and optical measurements of charge and density, calibration of the CCD image.

Measurement of frequency and amplitude of the first (l=1) diocotron mode for an electron column.

Measurement of the growth rate of the l=1 mode resistive instability.

Control of the l=1 mode via feedback technique.

Excitation of the l=1 mode and characterization of the autoresonance phenomenon.

Excitation of higher-order diocotron modes by means of rotating electric fields.

Measurement of the density profile as a function of time and determination of the radial diffusion coefficient.

Measurement of the parallel (axial) temperature of the electron plasma.
Prerequisites for admission
A solid knowledge of classical mechanics, electricity and magnetism is expected. Attendance to the MSc courses 'Classical electrodynamics' and 'Plasma physics and controlled fusion' can be useful, but is not deemed as necessary.
Teaching methods
The first part of the course consists of traditional lectures concerning the fundamental notions of plasma physics, experimental techniques and data analysis methods required to carry out the experiments. The second part is based on a series of laboratory experiments, accompanied by a general introduction and a collective discussion about methods and problems both expected a priori and identified a posteriori. Part of the time is reserved for discussion and critical assessment of data analysis and results.
Teaching Resources
Notes and articles concerning the experiments (handed out during the course).
Ronald C. Davidson, "Physics of Nonneutral Plasmas", Addison-Wesley, Redwood City, 1990 (excerpts).
Assessment methods and Criteria
The examination is based on the preparation of a report concerning the experiments carried out during the course and on a 45-60 minute oral discussion. The discussion deals with the physical and technical aspects of the experiments and is meant to assess the critical evaluation abilities and the skills acquired by the student during the course.
FIS/03 - PHYSICS OF MATTER - University credits: 6
Laboratories: 36 hours
Lessons: 21 hours