M.Sc. (Physics) curriculum, Tribhuvan University 2073

96

PHY671: Plasma Physics II 4 CH (L60+T20) Nature of the course: Theory Full Marks: 100 Pass Marks: 50

Course Description: The main aim of this course is to provide basic knowledge of plasma physics and develop skill in pursuing research work in plasma applications.

Course Objectives:

The objective of this course is to apply the knowledge and to lay the foundation on the fundamental study / research in plasma physics.

Course Contents:

1. Plasmas as Fluids [7 hours] 1.1 Introduction: The dielectric constant of a plasma, 1.2 The fluid equation of motion: The convective derivative, The stress tensor, Collisions,

Comparison with ordinary hydrodynamics, Langmuir’s paradox, Equation of continuity, Equation of state, The complete set of fluid equations,

1.3 Fluid drifts perpendicular to B, 1.4 Fluid drifts parallel to B: Boltzmann relation, 1.5 The plasma approximation.

2. Waves in Plasmas [16 hours]

2.1 Plasma oscillations, 2.2 Electron plasma waves, 2.3 Ion waves, 2.4 Validity of the plasma approximation, 2.5 Comparison of ion and electron waves, 2.6 Electrostatic electron oscillations perpendicular to B, 2.7 Electrostatic ion waves perpendicular to B, 2.8 The lower hybrid frequency, 2.9 Electromagnetic waves with B0 = 0, experimental applications, 2.10 Electromagnetic waves perpendicular to B0: Ordinary wave and Extraordinary wave, 2.11 Cutoffs and resonances, 2.12 Electromagnetic waves parallel to B0: The Whistler mode, Faraday rotation, 2.13 Hydromagnetic waves: Alfvén speed, 2.14 Magnetosonic waves, 2.15 The CMA diagram.

3. Diffusion and Resistivity [10 hours] 3.1 Diffusion and mobility in weakly ionized gases: Collision parameters, Diffusion

parameters, 3.2 Decay of a plasma by diffusion: Ambipolar diffusion, Diffusion in a slab, Diffusion in a

Cylinder, 3.3 Steady state solutions: Constant ionization function, Plane source, Line source 3.4 Recombination, 3.5 Diffusion across a magnetic field, 3.6 Collisions in fully ionized plasmas: Plasma resistivity, Mechanics of Coulomb collisions,

Physical meaning of η,

M.Sc. (Physics) curriculum, Tribhuvan University 2073

97

3.7 The single-fluid MHD equations, 3.8 Diffusion of fully ionized plasmas, 3.9 Solutions of the diffusion equation, 3.10 Bohm diffusion and neoclassical diffusion.

4. Equilibrium and Stability [6 hours] 4.1 Hydromagnetic equilibrium, 4.2 The concept of , 4.3 Diffusion of magnetic field into a plasma, 4.4 Classification of instabilities, 4.5 Two-stream instability, 4.6 The gravitational instability.

5. Kinetic Theory [9 hours]

5.1 Equations of kinetic theory: Boltzmann equation, Vlasov equation, Krook collision term, Fokker–Planck equation,

5.2 Derivation of the fluid equations: Equation of continuity, Momentum equation, 5.3 Plasma oscillations and Landau damping: The meaning of Landau damping, The kinetic

energy of a beam of electrons, The effect of initial conditions, 5.4 BGK and Van Kampen modes.

6. Nonlinear Effects [12 hours] 6.1 Sheaths: The necessity for sheaths, The planar sheath equation, The Bohm sheath

criterion, The Child–Langmuir law, Electrostatic probes, Langmuir probes, 6.2 Ion acoustic shock waves: The Sagdeev potential, The critical Mach numbers, Wave

steepening, Double layers, 6.3 The ponderomotive force: Self-focusing of laser, 6.4 Plasma echoes, 6.5 Reconnection, 6.6 Turbulence, 6.7 Sheath boundaries.

Text Book:

1. Chen F. F. – Introduction to Plasma Physics and Controlled Fusion (Third edition), Springer

International Publishing (2016).

Reference Books:

1. Krall N. A. and Trivelpiece A. W. – Principles of Plasma Physics, San Francisco Press (1986), 2. Bittencourt J. A. – Fundamentals of Plasma Physics (Fourth edition), Research Gate (on-line)

(2017), 3. Goldston R. J. and Rutherford P. H. – Introduction to Plasma Physics, IOP Publishing Ltd

(1995).