Collisionless Plasmas in Astrophysics

Collisionless Plasmas in Astrophysics examines the unique properties of media without collisions in plasma physics. Experts in this field, the authors present the first book to concentrate on collisionless conditions in plasmas, whether close or not to thermal equilibrium. Filling a void in scientific literature, Collisionless Plasmas in Astrophysics explains the possibilities of modeling such plasmas, using a fluid or a kinetic framework. It also addresses common misconceptions that even professionals may possess, on phenomena such as "collisionless (Landau) damping". Abundant illustrations are given in both space physics and astrophysics.

Gerard Belmont works as a "Directeur de Recherches" at the French CNRS since about twenty years. His activity is linked to space missions such as Cluster but is mainly of theoretical nature. He is a specialist of collisionless media, and their description through kinetic and fluid theories.

Roland Grappin received his PhD from the Paris VII University. Since 1979 he works as an Astronomer at the Paris Observatory in the LUTH ("Laboratoire Univers et th?ories"). His scientific activity covers turbulence in fluids and plasmas, dynamics of the solar wind, corona and transition region.

Fabrice Mottez is a scientist at the "Laboratoire Univers et th?ories" at the Paris Observatory. He has got his academic degree at the "Ecole Sup?rieure d'Electricit?" and a PhD of plasma physics at the Orsay-Paris XI University. He has devoted his career to collisionless space plasmas, the terrestrial and jovian magnetospheres, fundamental plasma physics, and numerical simulation. He has received the "Prix Plasma de la Soci?t? Fran?aise de Physique".

Filippo Pantellini has got his physics diploma at the ETH Z?rich and a PhD in astrophysics from the Paris VII University, followed by a two years postdoctoral fellowship in the astronomy unit at Queen Mary University London. His main research field covers the theoretical and numerical investigation of collisionless and weakly collisional space plasmas, with a particular interest for the solar wind and the solar corona.

Guy Pelletier is a professor at the University Joseph Fourier in Grenoble. He founded the theoretical group of the Laboratory for Astrophysics. The main activities were oriented towards the understanding of accretion-ejection flows, instabilities and transport in them, the environment of compact objects, the formation of relativistic flows, particle acceleration in them and their radiation; his main task during these last years was devoted to the physics of relativistic shocks, generation of supra-thermal particles and electromagnetic turbulence in them and their specific radiations. He has applied these theoretical works to Active Galactic Nuclei, especially Blazars, micro-quasars, Pulsar Wind Nebulae and Gamma Ray Bursts. He was nominated at the Institut Universitaire de France from 1995 to 2005.

PLASMA MODELS
Notion of Collisions in Plasma Physics
- Coulomb Interaction: A Long Range Interaction
- Kudesen Number
- "Collisionless" Plasmas and Low Collisionality
- Example: Collisionality in Solar Wind
Plasma Models: From Kinetic to Fluid
- Distribution Functions and Kinetic Equation
- Macroscopic Moments and Fluid Equations
- Demonstration of the Fluid Equations from the Kinetic One
- Closure of the Fluid System: "State Equation", Collisional vs Collisionless
- Fluid Equations and Thermodynamics
- Numerical Simulation. Fluid, Particle in Cell, and Hybrid Codes
Toy Models
- A few Examples to Understand the Fluid-Kinetic Relationship and the Role of Collisions
THE CASE OF MAGNETIZED PLASMAS
MHD and Kinetic Effects
- Fluid Equations in a Magnetized Plasma
- SLS Approximations and Mono-Fluid Description
- Ohm's Law and Generalized Ohm's Laws
- Departures from MHD: Multi-Fluid and Kinetic Effects
- Example: Interstellar Medium Phenomena
Characteristic Scales and Associated Plasma Properties
- Temporal and Spatial Scales
- Scale Ratios, Adimensional Numbers and Equations
- Main Dispersive Effects
- Example: Comparative Physics in Terrestrial Magnetosheath and Tokomak Fusion Device
PLASMA WAVES
Linear Waves, Dispersion, Polarization
- Field/Particle Coupling: Choice of Variables (j, E or v, B)
- Kinetic vs Fluid Treatments
Different Kinds of Waves and Associated Properties
- Waves in a Non Magnetized Plasma
- Waves in a Magnetized Plasma
- Role of Collisions
Importance of Waves
- Transports Induced by the Different Kinds of Waves
- Waves Used for Diagnosis (Radio Waves, Remote Sensing in Astrophysics, Whistler Mode)
Wave Modeling
- Waves and Simplified Maxwell's Equations (Electrostatic, Darwin Approximation, Hybrid Codes)
- Implicit Codes for Numerical Simulation
INSTABILITIES AND DAMPING
Two Kinds of Instabilities
- Fluid Instabilities
- Kinetic Instabilities
- Examples
Damping in Fluid Theories
- Dissipative Effects Due to Collisions and Damping Consequences
- Limit of Vanishing Collisions
Collisionless Damping
- Number of Eigenmodes: Fluid vs Kinetic
- A Simple Example: The Langmuir Wave, From Fluid to Kinetic
- Collisionless Damping: The Landau Effect
- Resonant Effects in Kinetic and Fluid Models
NON LINEAR EFFECTS AND TURBULENCE
Non Linear Structures and Turbulence
- The Fluid Point of View
- Wave-Wave Coupling
- Kinetic Structures. Particle Invariants, BGK Equilibria
- Quasi-Linear Effects, Trapping
- Electrostatic Double Layers
- Turbulence in a Magnetized Plasma: The Different Scales in Interaction
- Weak and Strong Turbulence
- Turbulence Models and Turbulent Heating
Collisionless Shocks and Discontinuities
- Non Linear Propagation, Discontinuities, Jumps
- Examples in Space Physics and Astrophysics
- Shocks in a Magnetized Plasma
- Microscopic Physics of the Shock Layers in a Collisionless Plasma
- Example: The Terrestrial Bow Shock, The Foreshocks
- Radiative Shoc ks in Astrophysics
FLOW AND PARTICLE ACCELERATION PROCESSES
Plasma Acceleration Processes
- Individual Particle Acceleration. Fermi and Other Processes
- Flow Acceleration and Heating
- Creation of Particle Beams
- Acceleration by Astrophysical Shocks
- Cosmic Ray Acceleration
- Magnetospheric Physics: Substorms and Auroras
Magnetic Reconnection
- Conservation of Connections in Ideal MHD
- Departure from the Ideal Ohm's Law: Microscopic Causes and Macroscopic Consequences
- 2-D Reconnection: Topological Definition and Energetic Consequences
- 3-D Reconnection
- Penetration of Solar Wind Plasma in the Magnetosphere
- Solar Coronal Heating: Reconnexion versus Turbulence
KINETIC-FLUID DUALITY: EXAMPLES
Solar/Stellar Wind Expansion
- Parker Model
- Exospheric Models
- Effective Closures
- Role of the Collisions
- Wind Created by a Rotating Magnetic Field (Pulsars)
Other Examples
CONCLUSIONS
Appendix: Upstream of Plasma Physics: Fields and Particles
- Electromagnetic Fields (Maxwell's Equation, Frames, Gauges)
- The Motion of Charged Particle (Lorentz Force, Motion, Guiding-Center, Collision of Two Particles)
- Notion of Conductivity, Dielectric Constant