Plasma Physics and Fusion Energy

Author: Jeffrey P. Freidberg  

Publisher: Cambridge University Press‎

Publication year: 2008

E-ISBN: 9780511271328

P-ISBN(Paperback): 9780521733175

Subject: O53 plasma physics

Keyword: 量子论

Language: ENG

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Plasma Physics and Fusion Energy

Description

There has been an increase in interest worldwide in fusion research over the last decade and a half due to the recognition that a large number of new, environmentally attractive, sustainable energy sources will be needed to meet ever increasing demand for electrical energy. Based on a series of course notes from graduate courses in plasma physics and fusion energy at MIT, the text begins with an overview of world energy needs, current methods of energy generation, and the potential role that fusion may play in the future. It covers energy issues such as the production of fusion power, power balance, the design of a simple fusion reactor and the basic plasma physics issues faced by the developers of fusion power. This book is suitable for graduate students and researchers working in applied physics and nuclear engineering. A large number of problems accumulated over two decades of teaching are included to aid understanding.

Chapter

Some closing comments on fusion power generation

3.5 Radiation losses

3.5.1 Overview of radiation losses

3.5.2 Calculation of W, the energy lost per particle per Coulomb collision

3.5.3 Calculation of SB

3.5.4 The effect of multiple ion species

3.6 Summary

Bibliography

The nuclear physics of fusion reactions

Bremsstrahlung radiation

Problems

4 Power balance in a fusion reactor

4.1 Introduction

4.2 The 0-D conservation of energy relation

4.3 General power balance in magnetic fusion

4.4 Steady state 0-D power balance

4.5 Power balance in the plasma

4.5.1 Ideal ignition

4.5.2 Ignition

4.6 Power balance in a reactor

4.6.1 The physics gain factor Q

4.6.2 The engineering gain factor Q

4.7 Time dependent power balance in a fusion reactor

4.7.1 Time dependent 0-D power balance relation

4.7.2 Thermal stability

4.7.3 The minimum external power

4.8 Summary of magnetic fusion power balance

Bibliography

Power balance in a fusion reactor

The Lawson criterion

Problems

5 Design of a simple magnetic fusion reactor

5.1 Introduction

5.2 A generic magnetic fusion reactor

5.3 The critical reactor design parameters to be calculated

5.4 Design goals, and basic engineering and nuclear physics constraints

5.4.1 Design goals

5.4.2 Engineering constraints

5.4.3 Nuclear physics constraints

5.5 Design of the reactor

5.5.1 Outline of the design calculation

5.5.2 The blanket-and-shield thickness

5.5.3 The plasma radius and coil thickness

The minimum cost

The minimum coil thickness

5.5.4 The major radius and plasma surface area and volume

5.5.5 Power density and plasma pressure

5.5.6 The plasma physics quantities beta and…

5.6 Summary

Bibliography

Reactor design overviews

Specific designs for ignition experiments and fusion reactors

Problems

Part II The plasma physics of fusion energy

6 Overview of magnetic fusion

6.1 Introduction

6.2 Basic description of a plasma

6.3 Single-particle behavior

6.4 Self-consistent models

6.5 MHD equilibrium and stability

6.6 Magnetic fusion concepts

6.7 Transport

6.8 Heating and current drive

6.9 The future of fusion research

Bibliography

Overview of Fusion

7 Definition of a fusion plasma

7.1 Introduction

7.2 Shielding DC electric fields in a plasma – the Debye length

7.2.1 A physical picture of Debye shielding

7.2.2 Derivation of the Debye length

7.3 Shielding AC electric fields in a plasma – the plasma frequency

7.3.1 A physical picture of the screening of AC fields

7.3.2 Derivation of the electron plasma frequency

7.4 Low collisionality and collective effects

7.4.1 A statistical picture of long-range collective effects

7.4.2 The inter-particle spacing versus the Coulomb interactive distance

7.4.3 The plasma frequency vs. the Coulomb collision frequency

7.5 Additional constraints for a magnetic fusion plasma

7.6 Macroscopic behavior vs. collisions

7.7 Summary

Bibliography

Problems

8 Single-particle motion in a plasma

8.1 Introduction

8.2 General properties of single-particle motion

8.2.1 Exact equations of motion

8.2.2 General conservation relations

8.3 Motion in a constant B field

8.3.1 Parallel motion

8.3.2 Perpendicular motion

8.3.3 Consequences of gyro motion

8.4 Motion in constant B and E fields: the drift

8.4.1 Effect of a parallel electric field

8.4.2 Effect of a perpendicular electric field

8.5 Motion in fields with perpendicular gradients: the ∇B drift

8.5.1 Perpendicular gradient in B with E = 0

8.5.2 Perpendicular gradient in E with uniform B

8.6 Motion in a curved magnetic field: the curvature drift

8.7 Combined V and V drifts in a vacuum magnetic fieldh

8.8 Motion in time varying E and B fields: the polarization drift

8.8.1 The polarization drift for…

Mathematical derivation

A physical picture

8.8.2 The polarization drift for…

Mathematical analysis

8.9 Motion in fields with parallel gradients: the magnetic moment and mirroring

8.9.1 The mathematical formulation

8.9.2 Solution to the equations

8.9.3 The mirror effect and the mirror machine

A qualitative picture of the mirror effect

The quantitative conditions for mirroring

The simple mirror machine

8.10 Summary – putting all the pieces together

Bibliography

Problems

9 Single-particle motion – Coulomb collisions

9.1 Introduction

9.2 Coulomb collisions – mathematical derivation

9.2.1 Formulation of the problem

9.2.2 Solution to the problem

9.3 The test particle collision frequencies

9.3.1 The general formulation

9.3.2 Evaluation of… and the integration over the impact parameter

9.3.3 Integration over target velocities

9.3.4 Properties of… and other collision frequencies

9.4 The mirror machine revisited

9.4.1 Calculation of…

9.4.2 Power balance in a simple mirror machine

9.5 The slowing down of high-energy ions

9.5.1 The high-energy-ion slowing down model

9.5.2 Which species is preferentially heated?

9.5.3 The alpha particle slowing down time

9.5.4 The fraction of alpha energy transferred to electrons and to ions

9.5.5 Discussion of beam heating

9.6 Runaway electrons

9.6.1 The threshold condition for runaway electrons

9.6.2 Properties of runaway electrons

9.7 Net exchange collisions

9.7.1 Formulation of the problem

9.7.2 The net momentum exchange collision rate

9.7.3 The net energy exchange collision rate

9.8 Summary

Bibliography

Problems

10 A self-consistent two-fluid model

10.1 Introduction

10.2 Properties of a fluid model

10.2.1 Macroscopic averages

10.2.2 Size of a fluid element

10.2.3 When is a plasma fluid model useful?

10.3 Conservation of mass

10.4 Conservation of momentum

10.4.1 The basic principle

10.4.2 The inertial force

10.4.3 The electric field force

10.4.4 The magnetic field force

10.4.5 The pressure gradient force

10.4.6 The collisional friction force

10.4.7 The conservation of momentum equations

10.5 Conservation of energy

10.5.1 The basic principle

10.5.2 The rate of change of internal energy

10.5.3 The compression work

10.5.4 Thermal conduction

10.5.5 The alpha power

10.5.6 The external auxiliary heating power

10.5.7 The ohmic heating power

10.5.8 Bremsstrahlung radiation

10.5.9 Energy equilibration

10.5.10 The conservation of energy equations

10.6 Summary of the two-fluid model

Bibliography

Problems

11 MHD – macroscopic equilibrium

11.1 The basic issues of macroscopic equilibrium and stability

11.2 Derivation of MHD from the two-fluid model

11.2.1 Basic scaling relations for MHD

11.2.2 The “obvious” simplifications

11.2.3 The single-fluid variables

11.2.4 The conservation of mass equations

11.2.5 The conservation of momentum equations

11.2.6 The conservation of energy equations

11.2.7 Summary of the MHD equations

11.3 Derivation of MHD from guiding center theory

11.3.1 The basic idea

11.3.2 The guiding center drift current and Ohm’s law

11.3.3 The magnetization current

11.3.4 The perpendicular MHD momentum equation

11.4 MHD equilibrium – a qualitative description

11.5 Basic properties of the MHD equilibrium model

11.5.1 The MHD equilibrium model

11.5.2 General properties – flux surfaces

11.5.3 General properties – current surfaces

11.5.4 General properties – magnetic pressure and tension

11.6 Radial pressure balance

11.6.1 The Phi-pinch

11.6.2 The Z-pinch

11.6.3 The screw pinch

11.6.4 General definition of beta in a screw pinch

11.7 Toroidal force balance

11.7.1 Introduction

11.7.2 The hoop force

11.7.3 The tire tube force

11.7.4 The 1/R force

11.7.5 The restoring force due to a perfectly conducting wall

11.7.6 The restoring force due to a vertical field

11.7.7 Analytic derivation of toroidal force balance

The model

The tire tube force Fp

The 1/R force FBφ

The hoop force FI

The vertical field force FV

The vertical field for toroidal force balance

Why bending a θ-pinch into a torus doesn’t work

11.7.8 Single particle picture of toroidal force balance

The pure toroidal θ-pinch

The Z-pinch and the screw pinch

11.7.9 Calculating the rotational transform

Rotational transform in a straight cylinder

Rotational transform in an axisymmetric torus

11.7.10 Toroidal force balance in configurations without toroidal current

The model magnetic field

The second order solution

11.8 Summary of MHD equilibrium

Bibliography

Problems

12 MHD – macroscopic stability

12.1 Introduction

12.2 General concepts of stability

12.2.1 Instabilities in physical systems

12.2.2 The frozen-in-field-line concept

12.2.3 Classifications of MHD instabilities

Internal and external modes

Pressure-driven and current-driven modes

Conducting wall vs. no wall configurations

12.3 A physical picture of MHD instabilities

12.3.1 Interchange modes

12.3.2 Ballooning modes

12.3.3 Current-driven instabilities

12.3.4 Single-particle picture of favorable and unfavorable curvature

12.4 The general formulation of the ideal MHD stability problem

12.4.1 The concept of linear stability

12.4.2 The MHD linear stability equations

12.4.3 A general property of linear MHD stability

12.5 The infinite homogeneous plasma – MHD waves

12.5.1 General derivation of MHD waves

12.5.2 The shear Alfvén wave

12.5.3 The compressional Alfvén wave

12.5.4 The sound wave

12.5.5 Summary

12.6 The linear Phi-pinch

12.6.1 The equilibrium and perturbation

12.6.2 The radial differential equation

12.6.3 Stability of the Phi-pinch

12.7 The m = 0 mode in a linear Z-pinch

12.7.1 Derivation of the differential equation

12.7.2 Stability of the m = 0 mode

12.7.3 Profile implications for stabilizing the m = 0 mode

12.8 The m = 1 mode in a linear Z-pinch

12.8.1 The Phi component of the momentum equation

12.8.2 The z component of the momentum equation

12.8.3 The r component of the momentum equation

12.8.4 Solution to the m = 1 eigenvalue equation

12.9 Summary of stability

Bibliography

Problems

13 Magnetic fusion concepts

13.1 Introduction

13.2 The levitated dipole (LDX)

13.2.1 Overview of the LDX

13.2.2 LDX equilibrium

The pressure profile

The global radial pressure balance relation

The poloidal magnetic field

The equilibrium beta limit

13.2.3 m = 1 stability

13.2.4 m = 0 stability

13.2.5 Summary of the levitated dipole

13.3 The field reversed configuration (FRC)

13.3.1 Overview of the FRC

13.3.2 The MTF concept

Creation

Translation

Compression

13.3.3 The FRC as a source of fusion energy

13.3.4 Summary of the FRC

13.4 The surface current model

13.4.1 Introduction

13.4.2 The 2-D surface current equilibrium

13.4.3 The perturbed magnetic field in the plasma

13.4.4 The perturbed magnetic field in the vacuum

13.4.5 The pressure balance matching condition

13.4.6 Summary of the surface current model

13.5 The reversed field pinch (RFP)

13.5.1 Overview of the RFP

13.5.2 RFP surface current equilibrium

13.5.3 RFP surface current stability

The plasma contribution

The vacuum contribution

The pressure balance matching condition

13.5.4 The m = 0 mode

13.5.5 The m = 1 mode

13.5.6 The resistive wall mode

The vacuum and resistive wall magnetic fields

The matching conditions

The resistive wall stability boundary

13.5.7 Summary

13.6 The spheromak

13.6.1 Overview of the spheromak

13.6.2 Spheromak surface current equilibrium

13.6.3 The m = 1 tilt instability

13.6.4 Summary of the spheromak

13.7 The tokamak

13.7.1 Overview of the tokamak

13.7.2 The circular cross section tokamak – equilibrium

The aspect ratio expansion

The surface current pressure balance relation

The equilibrium beta limit

13.7.3 The circular cross section tokamak – stability

The plasma contribution

The vacuum contribution

The pressure balance matching condition

The… kink instability

The… ballooning-kink instability

The Troyon beta limit

13.7.4 The non-circular cross section tokamak

The n = 0 axisymmetric instability

A more realistic n = 0 wire model

Stabilization of the n = 0 mode by a conducting wall

The n = 1 ballooning-kink instability

13.7.4 The advanced tokamak (AT)

The effect of a wall on the kink current limit

The effect of a wall on the ballooning-kink beta limit

13.7.5 The spherical tokamak (ST)

MHD beta limit in a spherical torus

Relation between beta and pressure in tokamaks

13.7.6 Summary of the tokamak

13.8 The stellarator

13.8.1 Overview of the stellarator

13.8.2 The Large Helical Device (LHD)

13.8.3 Guiding center particle orbits in a stellarator

Stellarator coordinates

The guiding center orbits in Boozer coordinates

13.8.4 The Wendelstein 7-X (W7-X)

13.8.5 The National Compact Stellarator Experiment (NCSX)

13.8.6 Summary

13.9 Revisiting the simple fusion reactor

13.9.1 Goal of the analysis

13.9.2 Reactor analysis

13.10 Overall summary

Bibliography

Advanced MHD theory

LDX

FRC-MTF

RFP

Spheromak

Tokamak

Spherical tokamak

Stellarator

Problems

14 Transport

14.1 Introduction

14.2 Transport in a 1-D cylindrical plasma

14.2.1 Fluid model

The starting equations

14.2.2 Calculating transport coefficients from the random walk model

Introduction

The random walk model

14.2.3 Particle diffusion in a magnetized plasma

Like particle analysis

Unlike particle analysis

Comparison with the fluid model and numerical values

14.2.4 Thermal conductivity of a magnetized plasma

14.2.5 Summary

14.3 Solving the transport equations

14.3.1 Temperature equilibration

14.3.2 Effect of the heating profile on the central temperature

14.3.3 Ohmic heating to ignition

The model

Approximate solution to the problem

Physical properties of the solution

Irony – too much confinement can be a disadvantage

14.3.4 Summary

14.4 Neoclassical transport

14.4.1 Introduction

14.4.2 Neoclassical transport due to passing particles

The half-transit time

The radial excursion

The step size

The transport coefficients

14.4.3 Neoclassical transport due to trapped particles

The fraction of trapped particles

The bounce frequency

The step size

The effective collision frequency

The trapped particle neoclassical transport coefficients

14.4.4 The bootstrap current

The trapped electron magnetization current

The passing electron magnetization current

The collision-driven bootstrap current

14.4.5 Summary

14.5 Empirical scaling relations

14.5.1 Introduction

14.5.2 Edge transport phenomena in a tokamak

The density limit

The L–H transition

Edge localized modes (ELMs)

Internal transport barriers

14.5.3 Empirical fit for E

Experimental procedure

Determining E

14.5.4 Summary

14.6 Applications of transport theory to a fusion ignition experiment

14.6.1 Introduction

14.6.2 A superconducting ignition experiment

The device volume

The constraints

Power balance

The minimum volume experiment

14.6.3 Heating to ignition

Thermal stability

The minimum power for ignition

14.6.4 The bootstrap fraction

Derivation of the bootstrap fraction

Standard monotonic profiles

AT profiles

14.6.5 Summary

14.7 Overall summary

Bibliography

General references

Neoclassical transport

Banana regime transport

The density limit

H mode

Internal transport barriers

Reversed shear

Scaling relations

Problems

15 Heating and current drive

15.1 Introduction

15.2 Ohmic heating

15.2.1 The ohmic heating model

15.2.2 Ohmic power balance

15.2.3 Thermal conduction losses

15.2.4 The ohmic power

15.2.5 Ohmic power balance

15.3 Neutral beam heating

15.3.1 Overview

15.3.2 How is a neutral beam produced?

15.3.3 The physics problem – energy required for beam penetration

15.3.4 The technology problem – conversion efficiency in the neutralizer

Positive ions

Negative ions

15.3.5 Summary

15.4 Basic principles of RF heating and current drive

15.4.1 Overview

15.4.2 RF sources and launching structures

15.4.3 Principles of electromagnetic wave propagation in a plasma

The dielectric tensor

Phase and group velocity

Cutoffs and wave resonances

Wave-particle resonances

Polarization

Reflection, transmission, absorption, and mode conversion

Accessibility

Summary

15.4.4 Analysis of electromagnetic wave propagation in a plasma

15.5 The cold plasma dispersion relation

15.6 Collisionless damping

15.6.1 Landau damping

15.6.2 X-mode cyclotron damping

15.6.3 O-mode cyclotron damping and generalized Landau damping

15.6.4 Summary

15.7 Electron cyclotron heating (ECH)

15.7.1 O-mode accessibility

15.7.2 O-mode absorption

15.7.3 X-mode accessibility

15.7.4 X-mode absorption

15.7.5 Summary

15.8 Ion cyclotron heating (ICH)

15.8.1 X-mode fundamental accessibility and polarization

15.8.2 Fast mode second harmonic accessibility

15.8.3 Fast mode second harmonic absorption

15.8.4 Fast wave minority accessibility

15.8.5 Fast wave minority absorption

15.8.6 Summary

15.9 Lower hybrid current drive (LHCD)

15.9.1 Overview

15.9.2 Lower hybrid accessibility

15.9.3 Slow wave power absorption

15.9.4 LHCD

15.9.5 Summary

15.10 Overall summary

Bibliography

Ohmic heating

Neutral beam heating

RF general

Landau damping

ECH

ICH

Lower hybrid heating and current drive

Problems

16 The future of fusion research

16.1 Introduction

16.2 Current status of plasma physics research

16.2.1 Macroscopic equilibrium and stability

16.2.2 Transport

16.2.3 Heating and current drive

16.2.4 Alpha particle plasma physics

16.2.5 Fusion technology issues

16.3 ITER

16.3.1 History

16.3.2 The new ITER

16.4 A demonstration power plant (DEMO)

Bibliography

Appendix A Analytic derivation of sigma

Appendix B Radiation from an accelerating charge

B.1 Definition of the radiation field

B.2 Calculation of A and φ from a time dependent source

B.3 Application to a single accelerating charge

B.4 Calculation of E and B

B.5 Calculation of the power radiated

Appendix C Derivation of Boozer coordinates

C.1 General coordinate transformation

C.2 The partial simplification to the cross-product form of Boozer coordinates

C.3 The partial simplification to the gradient form of Boozer coordinates

C.4 Elimination of the free functions…

C.5 Introduction of physical quantities into the Boozer coordinates

C.6 The guiding center orbits in Boozer coordinates

Appendix D Poynting’s theorem

Index

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