Contributors |
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xv | |
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xvii | |
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xix | |
Preface |
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xxi | |
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I Foundations of dynamo theory |
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1 | (198) |
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1 Introduction to self-excited dynamo action |
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3 | (56) |
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4 | (14) |
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4 | (4) |
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1.1.2 Thermodynamic equations |
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8 | (1) |
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1.1.3 Navier-Stokes equation |
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9 | (8) |
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1.1.4 Boundary conditions |
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17 | (1) |
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18 | (6) |
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18 | (2) |
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1.2.2 Chirality and geometry |
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20 | (1) |
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1.2.3 Basic mechanisms of dynamo action |
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20 | (2) |
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1.2.4 Fast and slow dynamos |
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22 | (2) |
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1.3 Necessary conditions for dynamo action |
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24 | (7) |
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1.3.1 Definitions of dynamo action |
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24 | (1) |
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1.3.2 Non-normality of the induction equation |
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24 | (1) |
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1.3.3 Flow velocity bounds |
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25 | (1) |
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1.3.4 Geometrical constraints |
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26 | (5) |
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1.4 Steady and time-dependent velocities |
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31 | (3) |
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1.4.1 Two simple examples |
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31 | (1) |
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32 | (2) |
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34 | (7) |
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1.5.1 The two-scale concept and Parker's model |
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34 | (1) |
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1.5.2 Mean field electrodynamics |
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35 | (3) |
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38 | (3) |
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1.6 Large magnetic Reynolds numbers |
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41 | (18) |
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1.6.1 Slow dynamos in flows |
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42 | (5) |
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1.6.2 The stretch-twist-fold picture |
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47 | (2) |
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1.6.3 Fast dynamos in smooth flows |
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49 | (1) |
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1.6.4 Fast dynamos in mappings |
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50 | (4) |
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1.6.5 The stretch-fold-shear model |
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54 | (5) |
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2 Nonlinearities and saturation |
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59 | (60) |
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2.1 General considerations |
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59 | (3) |
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2.2 Saturation of a dynamo generated by a periodic flow |
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62 | (5) |
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63 | (1) |
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2.2.2 The G.O. Roberts dynamo |
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64 | (1) |
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2.2.3 Saturation of dynamos driven by the α-effect |
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65 | (2) |
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2.3 Saturation in the low Re limit in the vicinity of the dynamo threshold |
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67 | (3) |
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2.3.1 A Ponomarenko type dynamo as a tractable problem without scale separation |
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67 | (1) |
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2.3.2 Structure of the perturbation analysis |
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68 | (1) |
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2.3.3 The laminar scaling |
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69 | (1) |
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2.4 Saturation in the high Re limit in the vicinity of the dynamo threshold |
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70 | (2) |
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2.4.1 Dimensional arguments |
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70 | (1) |
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2.4.2 High Re dynamos close to the bifurcation threshold |
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71 | (1) |
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72 | (3) |
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2.5.1 Weak and strong field regimes of the geodynamo |
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72 | (1) |
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2.5.2 Further comments on weak and strong field regimes |
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73 | (1) |
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2.5.3 Scalings of magnetic energy using dimensional considerations |
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74 | (1) |
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2.6 Scaling laws in the limit of large Rm and Re |
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75 | (4) |
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2.6.1 Effect of turbulence on the dynamo threshold |
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76 | (1) |
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2.6.2 Batchelor's predictions for turbulent dynamo threshold and saturation |
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77 | (1) |
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2.6.3 A Kolmogorov type scaling in the limit Re << Rm << Rmc |
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78 | (1) |
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2.7 Nonlinear effects in mean field dynamo theory |
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79 | (18) |
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2.7.1 Nonlinear effects in the mean field formalism |
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81 | (7) |
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2.7.2 MHD turbulence theories |
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88 | (4) |
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2.7.3 Direct numerical simulations |
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92 | (5) |
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2.8 Physically-realistic Faraday-disc self-excited dynamos |
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97 | (22) |
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98 | (2) |
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2.8.2 Characteristics of self-excited dynamos |
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100 | (1) |
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2.8.3 Governing equations in dimensional form |
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101 | (2) |
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2.8.4 Energetics and equilibrium solutions |
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103 | (2) |
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2.8.5 Dimensionless equations |
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105 | (2) |
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107 | (1) |
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2.8.7 Survey of behaviour |
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108 | (3) |
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2.8.8 Some numerical integrations |
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111 | (8) |
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3 Dynamics of rotating fluids |
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119 | (80) |
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3.1 Boundary and shear layers in rotating flows |
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120 | (16) |
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121 | (3) |
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3.1.2 Sidewall E1/3--layers |
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124 | (3) |
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3.1.3 Sidewall E1/4--layers |
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127 | (4) |
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3.1.4 Differentially rotating spheres: The Proudman--Stewartson problem |
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131 | (5) |
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3.2 Boundary and shear layers in rotating MHD flows |
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136 | (15) |
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137 | (2) |
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3.2.2 Differentially rotating spheres |
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139 | (3) |
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3.2.3 The Ekman--Hartmann layer |
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142 | (3) |
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3.2.4 Rotating MHD free shear layers; Λ M >> 1 |
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145 | (6) |
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151 | (17) |
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151 | (8) |
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159 | (1) |
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3.3.3 MHD waves in rotating fluids |
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160 | (5) |
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3.3.4 Stratified rotating MHD waves |
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165 | (3) |
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3.4 Convection in rotating spherical fluid shells |
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168 | (31) |
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3.4.1 Physical motivations |
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168 | (1) |
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3.4.2 Convection in the rotating cylindrical annulus |
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169 | (8) |
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3.4.3 Mathematical formulation of the problem of convection in rotating spherical shells |
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177 | (2) |
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3.4.4 The onset of convection in rotating spherical shells |
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179 | (4) |
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3.4.5 Onset of inertial convection at low Prandtl numbers |
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183 | (1) |
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3.4.6 Evolution of convection columns at moderate Prandtl numbers |
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184 | (6) |
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3.4.7 Finite amplitude convection at higher Prandtl numbers |
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190 | (3) |
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3.4.8 Finite amplitude inertial convection |
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193 | (2) |
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3.4.9 Penetrative and compositional convection |
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195 | (2) |
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3.4.10 Concluding remarks on convection |
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197 | (2) |
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II Natural dynamos and models |
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199 | (214) |
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201 | (56) |
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4.1 The Earth and its magnetic field |
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201 | (8) |
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201 | (1) |
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4.1.2 Structure of the Earth |
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202 | (2) |
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4.1.3 The geomagnetic field |
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204 | (3) |
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207 | (2) |
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4.2 Governing equations and parameters |
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209 | (3) |
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4.3 Fundamental theoretical results |
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212 | (7) |
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4.3.1 Taylor's constraint |
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212 | (2) |
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4.3.2 The "arbitrary" geostrophic flow uG(S) |
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214 | (1) |
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4.3.3 Ekman states, Taylor states and model-Z: determination of the geostrophic flow uG |
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215 | (2) |
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4.3.4 The role of inertia |
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217 | (2) |
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4.4 Parameter constraints |
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219 | (4) |
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220 | (1) |
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4.4.2 The magnetic Reynolds number |
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221 | (1) |
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222 | (1) |
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4.4.4 The Rayleigh number |
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222 | (1) |
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4.4.5 The magnetic Ekman number |
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223 | (1) |
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223 | (6) |
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4.5.1 Nonlinear α2 and αω models |
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224 | (1) |
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224 | (1) |
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225 | (4) |
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4.6 Turbulence in the Earth's core: the ends justify the means? |
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229 | (2) |
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4.7 Preliminary considerations on turbulence |
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231 | (8) |
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231 | (1) |
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4.7.2 Orders of magnitude |
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232 | (2) |
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4.7.3 Basic equations and their averages |
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234 | (1) |
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4.7.4 Qualitative descriptions of turbulence |
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235 | (4) |
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4.8 The traditional approach to turbulence |
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239 | (10) |
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4.8.1 A three-step program |
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239 | (1) |
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4.8.2 Linearised modes of a simple model |
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240 | (2) |
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4.8.3 The most easily excited mode |
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242 | (2) |
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4.8.4 More complicated and less complicated models |
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244 | (2) |
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246 | (2) |
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4.8.6 An alternative application: DNS |
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248 | (1) |
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4.9 The engineering approach to turbulence |
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249 | (4) |
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249 | (1) |
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4.9.2 Similarity and dynamical similarity |
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250 | (2) |
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252 | (1) |
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4.10 Where are we now, and the future |
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253 | (4) |
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253 | (1) |
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4.10.2 A critical summary of turbulence |
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254 | (3) |
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257 | (24) |
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5.1 Observations of planetary magnetic fields |
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257 | (6) |
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5.2 Some outstanding problems in planetary dynamo theory |
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263 | (2) |
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5.3 Conditions needed for dynamo action in planets |
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265 | (2) |
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5.4 Energy sources for planetary dynamos |
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267 | (2) |
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5.5 Internal structure of the planets |
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269 | (4) |
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272 | (1) |
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273 | (1) |
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5.6 Dynamics of planetary interiors |
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273 | (5) |
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5.6.1 Typical velocity and field estimates |
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276 | (2) |
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5.7 Numerical dynamo models for the planets |
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278 | (3) |
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281 | (32) |
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6.1 Stellar magnetic activity |
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281 | (3) |
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6.2 Linear αω--dynamos for the solar cycle |
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284 | (7) |
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285 | (2) |
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287 | (1) |
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287 | (1) |
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288 | (2) |
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290 | (1) |
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6.2.6 Meridional circulation |
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291 | (1) |
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6.3 Nonlinear quenching mechanisms |
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291 | (2) |
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293 | (4) |
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6.4.1 Spherical interface models |
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294 | (1) |
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295 | (2) |
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6.5 Modulation of cyclic activity |
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297 | (11) |
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6.5.1 Deterministic modulation |
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299 | (5) |
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304 | (3) |
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6.5.3 On--off and in--out intermittency |
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307 | (1) |
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6.6 Rapidly rotating stars |
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308 | (3) |
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311 | (2) |
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313 | (48) |
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313 | (3) |
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7.2 Interstellar medium in spiral galaxies |
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316 | (5) |
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7.2.1 Turbulence and multi-phase structure |
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316 | (3) |
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319 | (2) |
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7.3 Magnetic fields observed in galaxies |
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321 | (3) |
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7.4 The origin of galactic magnetic fields |
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324 | (18) |
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7.4.1 Mean-field models of the galactic dynamo |
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325 | (10) |
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7.4.2 The fluctuation dynamo and small-scale magnetic fields |
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335 | (3) |
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7.4.3 Magnetic helicity balance in the galactic disc |
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338 | (4) |
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7.5 Observational evidence for the origin of galactic magnetic fields |
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342 | (11) |
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7.5.1 Magnetic pitch angle |
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342 | (2) |
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7.5.2 The even (quadrupole) symmetry of magnetic field in the Milky Way |
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344 | (2) |
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7.5.3 The azimuthal structure |
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346 | (2) |
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7.5.4 A composite magnetic structure in M51 and magnetic reversals in the Milky Way |
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348 | (2) |
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7.5.5 The radial magnetic structure in M31 |
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350 | (2) |
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7.5.6 Strength of the regular magnetic field |
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352 | (1) |
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353 | (2) |
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7.6.1 Turbulent interstellar gas in elliptical galaxies |
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354 | (1) |
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7.6.2 The fluctuation dynamo in elliptical galaxies |
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354 | (1) |
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355 | (3) |
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358 | (3) |
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8 Survey of experimental results |
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361 | (48) |
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361 | (3) |
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8.2 Description of the experiments |
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364 | (20) |
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8.2.1 A rapidly rotating disc in a cylinder of sodium |
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365 | (1) |
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8.2.2 A dynamo with two solid rotating cylinders |
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365 | (1) |
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8.2.3 The α--box experiment |
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366 | (2) |
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8.2.4 A precessing experiment in liquid sodium |
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368 | (1) |
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8.2.5 The first Ponomarenko type experiment |
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369 | (1) |
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8.2.6 The vortices of gallium |
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370 | (2) |
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372 | (2) |
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8.2.8 The Karlsruhe dynamo |
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374 | (2) |
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8.2.9 The College Park experiments |
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376 | (1) |
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8.2.10 Von Karman Sodium experiments |
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377 | (1) |
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8.2.11 Derviche Tourneur Sodium project |
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378 | (1) |
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8.2.12 The Madison project |
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379 | (1) |
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379 | (1) |
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8.2.14 The Socorro project |
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380 | (1) |
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8.2.15 A new precessing project in sodium |
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380 | (1) |
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8.2.16 Technology and measurements in dynamo experiments |
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380 | (4) |
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8.3 What have we learnt from the experimental approach? |
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384 | (21) |
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384 | (1) |
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8.3.2 Magnetic field expulsion |
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385 | (1) |
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386 | (3) |
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389 | (1) |
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8.3.5 The experimental approach to a kinematic dynamo |
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390 | (4) |
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8.3.6 The onset of dynamo action |
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394 | (3) |
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8.3.7 The effect of turbulence |
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397 | (2) |
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399 | (3) |
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8.3.9 The β-effect and turbulent viscosity |
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402 | (2) |
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8.3.10 Saturation of the dynamo |
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404 | (1) |
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405 | (4) |
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409 | (4) |
A Vectors and coordinates |
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413 | (4) |
B Poloidal--Toroidal decomposition |
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417 | (2) |
C Taylor's constraint |
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419 | (6) |
D Units |
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425 | (2) |
E Abbreviations |
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427 | (2) |
References |
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429 | (42) |
Reference Index |
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471 | (8) |
Subject Index |
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479 | |