The earth's ionosphere : plasma physics and electrodynamics

580 Pages·2009·19.66 MB·English

by  Michael C Kelley

The Earth’s Ionosphere
Plasma Physics and Electrodynamics
Second Edition
Michael C. Kelley
Cornell University
College of Engineering
School of Electrical and Computer Engineering
Ithaca, NY
AMSTERDAM•BOSTON•HEIDELBERG•LONDON
NEWYORK•OXFORD•PARIS•SANDIEGO
SANFRANCISCO•SINGAPORE•SYDNEY•TOKYO
AcademicPressisanimprintofElsevier
The Earth's Ionosphere, 2nd Edition
Kelley
Table of Contents
Table of Contents
Preface
Chapter 1 Introductory and Background Material
1.1 Scope and Goals of the Text
1.1.1 Historical Perspective
1.1.2 Organization and Limitations
1.2 Structure of the Neutral Atmosphere and the Main Ionosphere
1.3 D-Region Fundamentals
1.4 The Earth's Magnetic Field and Magnetosphere
1.5 Problem Set
References
Chapter 2 Fundamentals of Ionospheric and Magnetospheric Plasma Dynamics
2.1 The Basic Fluid Equations
2.1.1 Conservation of Mass
2.1.2 Equation of State
2.1.3 Momentum Equation for the Neutral Fluid
2.1.4 Momentum Equations for the Plasma
2.1.5 The Complete Equation Sets
2.2 Steady-State Ionospheric Plasma Motions Due to Applied Forces
2.3 Generation of Electric Fields
2.4 Electric Field Mapping
2.5 Elements of Magnetospheric Physics
2.5.1 The Guiding Center Equations and the Adiabatic Invariants
2.5.2 Magnetohydrodynamics
2.6 Are Ionospheric Electric Fields Real?
2.7 Coordinate Systems

2.8 Problem Set
References
Chapter 3 Dynamics and Electrodynamics of the Equatorial Zone
3.1 Motions of the Equatorial F Region: The Data Base
3.2 The Equatorial F-Region Dynamo
3.3 E-Region Dynamo Theory and the Daytime Equatorial Electrojet
3.4 Further Complexities of Equatorial Electrodynamics
3.4.1 The Prereversal Enhancement
3.4.2 High-Latitude Effects on the Equatorial Electric Field
3.5 Feedback Between the Electrodynamics and Thermospheric Winds
3.6 Mesospheric and Lower Thermospheric Dynamics
3.6.1 Atmospheric Winds in the Mesosphere and Lower Thermosphere
3.6.2 A Primer on Turbulence and the Turbopause
3.7 Problem Set
References
Chapter 4 Equatorial Plasma Instabilities and Mesospheric Turbulence
4.1 F-Region Plasma Instabilities: Observations
4.2 Development and Initiation of Convective Ionospheric Storms (a.k.a. Equatorial Spread F)
4.2.1 Linear Theory of the Rayleigh-Taylor Instability
4.2.2 The Generalized Rayleigh-Taylor Process: Electric Fields, Neutral Winds, and
Horizontal Gradients
4.2.3 The Seeding of Convective Ionospheric Storms by Gravity Waves
4.2.4 Role of Velocity Shear in Convective Ionospheric Storms
4.2.5 Summary of Linear Theory Results
4.3 Nonlinear Theories of Convective Ionospheric Storms
4.3.1 Two-Dimensional Computer Simulations
4.3.2 Simulations Including Seeding and Shear
4.3.3 Summary of Nonlinear Theory Results
4.4 Linkage of Large and Small Scales in CEIS
4.4.1 Evidence for a Diffusive Subrange
4.4.2 The Diffusive Subrange
4.4.3 Toward a Unified Theory for the Convective Ionospheric Storm Spectrum
4.5 Convective Ionospheric Storms Summary
4.6 E-Region Plasma Instabilities: The Observational Data Base
4.7 Linear Theories of Electrojet Instabilities
4.8 Nonlinear Theories of Electrojet Instabilities
4.8.1 Two-Step Theories for Secondary Waves
4.8.2 On the Observations that the Phase Velocity of Type I Equatorial Waves is
Independent of Angle
4.8.3 Nonlinear Gradient Drift Theories
4.8.4 Nonlinear Studies of Farley-Buneman (FB) Waves
4.9 D-Region Turbulence
4.10 Future Directions
4.11 Problem Set
References
Chapter 5 Hydro- and Electro-dynamics of The Mid-Latitude Ionosphere
5.1 Introduction to the Tropical and Mid-Latitude Ionospheres
5.1.1 Background Material
5.1.2 On the Height of the Daytime F2 Layer
5.1.3 Equations Including Vertical Flux Without Winds or Electric Fields
5.1.4 F-Layer Solutions with Production, Diffusion, and Flux
5.1.5 More General Nighttime Solutions
5.1.6 The Appleton Anomaly: An Equatorial Electric Field Effect
5.1.7 The Corotation Electric Field and Formation of the Plasmasphere
5.2 Electric Fields in the Tropical and Mid-Latitude Zone
5.2.1 Electric Field Measurements
5.2.2 Neutral Wind Effects
5.2.3 Combined Effects of Electric Fields and Neutral Winds
5.2.4 Complexities of the Real Nighttime Tropical Ionosphere
5.2.5 The Transition Zone between Mid and High Latitudes
5.3 Mid-Latitude Lower Thermosphere Dynamics
5.3.1 Tidal Effects
5.3.2 Wind Profiles
5.4 Problem Set
References
Chapter 6 Waves and Instabilities at Mid-Latitudes
6.1 Mesoscale Vertical Organization of Ionospheric Plasma: General Considerations
6.2 Oscillations of the Neutral Atmosphere
6.3 Role of Gravity Waves and Tides in Creating Vertical Ionospheric Structure
6.4 Effects of Particle Precipitation at Mid-Latitudes
6.5 Horizontal Structure in the Midlatitude Ionosphere
6.6 Mid-Latitude F-Region Plasma Instabilities
6.6.1 F-Region Plasma Instabilities in the Equatorial Anomaly (Equatorial Arc) Region
6.6.2 Local Mid-Latitude F-Region Plasma Instabilities: A New Process
6.6.3 Linear Theory for the Perkins Instability
6.7 Mid-Latitude E-Region Instabilities
6.7.1 Radiowave Observations of Nighttime Mid-Latitude E-Region Instabilities
6.7.2 The Wavelength Limiting Effect
6.7.3 Multi-Experimental Observations of Mid-Latitude Structures
6.7.4 Mid-Latitude E-Region Instabilities: Difficulties with Simple Explanations
6.7.5 The Effect of a Wind Shear: The Kelvin-Helmholtz Instability as a Source of
Q-P Echoes
6.7.6 The Role of Horizontal Structure: Amplification by the Cowling Effect
6.7.7 Spontaneous Structuring by the Es Layer Instability
6.7.8 Coupling of Es Layers and the F Layer
6.7.9 The Wavelength Limiting Effect and Small-Scale Instabilities
6.7.10 Wind-Driven Thermal Instabilities
6.8 Problem Set
References
Chapter 7 Dynamics and Electrodynamics of the Mesosphere
7.1 Noctilucent Clouds (NLC) and the Temperature Anomaly
7.2 Gravity Wave Breaking
7.3 The Polar Summer Mesosphere: A Wave-Driven Refrigerator
7.4 New Observations of NLC and Related Phenomena
7.5 Polar Mesosphere Summer Echoes (PMSE)
7.6 The Role of Charged Ice
7.7 On the Possible Relationship Between PMSE, NLC, and Atmospheric Change
7.8 Upward-Propagating Lightning
7.9 Nonlinear Mesospheric Waves
7.9.1 Observations
7.9.2 Analogy to a Hydrolic Jump
7.9.3 Nonlinear Simulation of Mesospheric Bores
7.10 Problem Set
References
Chapter 8 High-Latitude Electrodynamics
8.1 Electrical Coupling between the Ionosphere, Magnetosphere, and Solar Wind
8.1.1 General Relationships
8.1.2 A Qualitative Description for Southward IMF
8.1.3 Energy Transfer
8.1.4 Additional Complexities
8.2 Observations of Ionospheric Convection
8.2.1 Observations during Southward IMF
8.2.2 Observations during Northward IMF
8.3 Simple Models of Convection in the Magnetosphere
8.3.1 Models for Southward IMF
8.3.2 Models for Northward IMF
8.4 Empirical and Analytic Representations of High-Latitude Convection
8.5 Observations of Field-Aligned Currents
8.5.1 Current Patterns for a Southward IMF
8.5.2 Current Patterns for a Northward IMF
8.5.3 Dependence on Magnetic Activity, IMF, and Season
8.6 Horizontal Currents at High Latitudes
8.7 Problem Set
References
Chapter 9 Ionospheric Response to Electric Fields
9.1
Ionospheric Effects of Parallel Plasma Dynamics
9.1.1 Ionospheric Composition at High Latitudes
9.1.2 Hydrodynamic Theory of the Polar Wind
9.2 Ionospheric Effects of Perpendicular Plasma Dynamics
9.2.1 The Role of Horizontal Transport
9.2.2 Ion Heating Due to Collisions
9.2.3 Velocity-Dependent Recombination
9.2.4 Positive and Negative Ionospheric Storms
9.3 Electrodynamic Forcing of the Neutral Atmosphere
9.3.1 J×B Forcing
9.3.2 Global Observations and Simulations
9.4 Particle Acceleration in the Topside Ionosphere
9.4.1 Parallel Electric Fields in the Upper Ionosphere
9.4.2 Ion Outflows and Perpendicular Ion Acceleration
9.5 Summary
9.6 Problem Set
References
Chapter 10 Instabilities and Structure in the High-Latitude Ionosphere
10.1 Planetary and Large-Scale Structures in the High-Latitude F Region
10.1.1 Convection and Production as Sources of Planetary Scale Structure in the High-
Latitude lonosphere
10.1.2 Some Effects of Plasma Transport and Loss on the Large-Scale Horizontal
Structure of the Ionosphere
10.1.3 Longitudinal Structures due to Localized Sub-Auroral Electric Fields
10.1.4 Temperature Enhancements in the Trough and Stable Auroral Red Arcs
10.1.5 Horizontal Plasma Variations Due to Localized Plasma Production and Heating
10.1.6 Summary
10.2 Intermediate-Scale Structure in the High-Latitude F Region
10.2.1 The Generalized E×B lnstability at High Latitudes
10.2.2 Turbulent Mixing as an Alternative to Plasma Instabilities
10.2.3 Diffusion and lmage Formation
10.3 Small-Scale Waves in the High-Latitude F Region
10.4 E-Region Layering at High Latitudes
10.5 Plasma Waves and Irregularities in the High-Latitude E Region: Observations
10.5.1 Radar Observations
10.5.2 Rocket Observations of Auroral Electrojet Instabilities
10.5.3 Simultaneous Data Sets
10.5.4 Summary
10.6 Linear Auroral Electrojet Wave Theories
10.6.1 The Gradient Drift Instability
10.6.2 The Two-Stream Instability and Type 4 Radar Echoes
10.6.3 Type 3 Radar Echoes: Are They Due to Ion Cyclotron Waves?
10.6.4 Nonlinear Theories
10.7 Summary
10.8 Problem Set
References
Appendix A Ionospheric Measurement Techniques
A.1 Radio Wave Techniques in Ionospheric Physics
A.1.1. Incoherent Scatter Radars
A.1.2 Coherent Scatter Radars
A.1.3 Scintillation Techniques
A.2 Optical Methods
A.2.1 Airglow
A.2.1.1 The 557.7 nm Emission
A.2.1.2 The NIR OH Broadband Emission
A.2.1.3 The 630.0 nm Emission
A.2.1.4 Oxygen Recombination Lines
A.2.2 Lidar
A.2.2.1 Fabry-Pérot Interferometery Thermospheric/Ionospheric Measurements
A.2.2.2 Particulars of the FPI
A.2.2.3 An Example of a Contemporary FPI
A.3 In Situ Measurements
A.3.1 Langmuir Probes, Retarding Potential Analyses, and Drift Meters
A.3.1.1 Electron Temperature Measurements-the Langmuir Probe
A.3.1.2 Ion Temperature and Density Measurements—the Retarding Potential
Analyzer
A.3.1.3 Ion Drift Velocity Measurements—the Ion Drift Meter
A.3.1.4 Ion Composition Measurements-the Mass Spectrometer
A.3.2 Electric Current, Measurements—the Fluxgate Magnetometer
A.3.2.1 Other Current Measurement Technology
A.3.3 Double-Probe Electric Field Detectors
A.3.4 Electrostatic Wave Measurements
A.3.5 Barium Ion Cloud Measurements
References
Appendix B Reference Material and Equations
B.1 Atmospheric and Ionospheric Structure
B.2 Miscellaneous Formulas
B.3 Surface Magnetic Field Measurements and Magnetic Activity Indices
B.4 Websites of Interest
References
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p.cm.–(Internationalgeophysicsseries;v.96)
ISBN978-0-12-088425-4(hardcover:alk.paper)1.Spaceplasmas.2.Plasma
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Preface
During the past five decades, the underlying physical principles upon which
ionospheric research is based have undergone a drastic change. Prior to this
period,themainemphasiswasonproductionandlossofelectronsandionsby
photoionizationandparticlebeams.Ionchemistry,geomagneticfieldvariations,
and other “aeronomical” processes formed primary subfields as well. With the
development of incoherent scatter radar techniques as well as scientific satel-
lites,awholenewrealmofionosphericprocessesbecameamenabletoscientific
study.Inparticular,spacescientistswereabletoreliablyprobethedynamicsof
the ionosphere and to realize the fundamental role played by electric fields. In
a parallel development, the physics of plasmas became an important branch of
scienceduetoitsroleincontrolledfusionresearch.
In this book, study of the plasma physics and electrodynamics of the iono-
sphereisgiventhehighestpriority,andsomeclassicalaeronomicalprocessesare
deemphasized. This is an unfortunate necessity, but the text by Rishbeth and
Garriott(1969),publishedinthesameInternationalGeophysicsSeries,remains
avaluabletreatiseonthesetopics,andanewpublicationbySchunkandNagy
(2000)isexcellentinthisarea.
The ionosphere is somewhat of a battleground between the earth’s neutral
atmosphereandthesun’sfullyionizedatmosphereinwhichtheearthisimbed-
ded.Oneofthechallengesofionosphereresearchistoknowenoughaboutthese
twovastfieldsofresearchtomakesenseoutofionosphericphenomena.Wetryto
givethereadersomeinsightsintohowthesecompetingsourcesofmass,momen-
tum, and energy vie for control of the ionosphere. Unlike the first edition, we
nowincludetheDregionoftheionosphere.Becausetheneutralatmosphereso
dominatesthephysics,weincludediscussionsofturbulencethroughoutthetext
whereappropriate.Thehugeincreasesindusty/icyplasmaphysicsandtherole
polarmesosphericcloudsmayplayinGlobalChangearereasonstoincludethis
region.
Aftersomeintroductorymaterial,thestudyisbeguninearnestwiththeequa-
torialionosphere.Heretheearth’smagneticfieldishorizontalandmanyunique
andfascinatingphenomenaoccur.ItisinterestingtonotealsothattheCoriolis
forcevanishesatthegeographicequator,whichmakesforsomeunusualocean
andatmosphericdynamicsaswell.InChapter3theelectrodynamicsofthiszone
arestudied,andplasmainstabilitiesarediscussedinChapter4.Thisparticular
chapterisextendedgreatlyfromthefirstedition.
xiv Preface
In Chapter 5 the midlatitude zone is studied, and, in particular, the role of
gravitywavesandneutralwinddynamicsisemphasized.Thisistheionospheric
footprintofthatportionofthenear-spaceregionoftheearththatisdominated
by the planet’s rotation. Due to the explosion of information on midlatitude
instabilities,anewChapter6hasbeenwritten.Theroleoftheneutralwindin
theseinstabilitiessimplywasnotrecognizedinthe1980s.
Anentirelynewchapterdealingwiththepolarsummermesospherehasbeen
writtenduetothehugeincreaseininterestandourunderstandingofthisregion.
The role of charged ice in an icy (or dusty) plasma has led to this new interest,
ashasthepossibilityofglobalchangebeingdetectedearlyinthisregion.
In Chapter 8 the interaction of the solar wind with the magnetic field of the
earthisreviewed,withparticularregardtotheimpositionofelectricfieldsand
field-aligned currents on the ionosphere. At high latitudes the imposed electric
field from this source overcomes the field due to the rotation of the earth. The
influenceoftheinterplanetarymagneticfieldisdescribed,asaretheflowpatterns
that arise in the ionosphere. The effect of these electric fields on ionospheric
plasma as well as on the neutral atmosphere is the topic of Chapter 9. In the
final chapter, a number of processes that create structure in the high-latitude
ionosphere are presented, including, but not limited to, the plasma instabilities
thatoccurthere.
As is already evident, the D region and mesosphere are included in this new
addition.ProblemsareaddedonthecompanionWebsitetofacilitateusingthe
bookasatextbook.Asolutionsmanualisavailabletoteachers.
Iamverymuchindebtedtolegionsofstudentswhohavereadandconstruc-
tivelycriticizedthetextasitevolved,aswellastomymanycolleaguesatCornell
and throughout the world. The study of space plasma physics is by definition
an international discipline and epitomizes the way in which the human race
can cooperate perfectly well at the highest technical and interpersonal levels.
I have learned a great deal about both space physics and my fellow passengers
onSpaceshipEarthwhiletravelingaroundtovariousrocketranges,radarobser-
vatories,andscientificlaboratories.SpecialthanksgotoRodHeelis,whohelped
considerablywithChapters7and8inthefirstedition,andtomyeditor,Laurie
Shelton,forherskillandendlesspatience.
MichaelC.Kelley
August19,2008