Les deuxiernes "Rencontres de l'Observatoire", qui ont eu lieu a l'Observatoire de Paris a Meudon du 10 au 14 Janvier 2000, ont reuni autour du theme "Problernes ernergents en physique de I'espace" 120 physiciens et astrophysiciens venus d'une vingtaine de pays differents. Nous avons voulu honorer a cette occasion Jean-Louis Steinberg pour ses con- tributions majeures a la recherche spatiale, ala radioastronomie et a la physique de I'espace. L'approche explicitement pluridisciplinaire de ce colloque, qui ne s'est pas laisse confiner dans les limites etroites de la physique spatiale ni dans celles imposees par certains programmes officiels, suit l'esprit de sa carriere scientifique: sortir des limites des sujets deja etudies ou sur Ie point de l'etre, et appliquer les connaissances acquises pour explorer de nouveaux domaines. Ce dernier quart de siecle a vu une croissance vertigineuse des performances spatiales. La technologie moderne ne perrnet pas encore de jongler avec les univers comme Ie prestidigitateur de Grandville (Grandville, Un autre monde, ed. H. Four- nier, Paris, 1844); mais quelques decades ont suffi pour voir des instruments soph- istiques explorer les frontieres du systerne solaire, et la cornmunaute de la recher- che spatiale a depasse rapidement Ie sujet etroit de I'environnement soleil-terre pour s'interesser a I'ensemble de l'heliosphere, OU les memes processus physiques sont a I'ceuvre.

Table of Contents:
A Critical Review of Sun-Space Physics.- Acceleration and Transport of Energetic Charged Particles in Space.- Various Regimes of Cosmic Ray Diffusion in Turbulent Magnetic Fields.- Non Gaussian and Non Local Transport in the Earth’s Distant Magnetotail.- Acceleration and Transport of Particles in Collisionless Plasmas: Wakes due to the Interaction with Moving Bodies.- Observational Evidence of Dissipative Small Scale Processes: Geotail Spacecraft Observation and Simulation of Electrostatic Solitary Waves.- Instabilities and Formation of Coherent Structures.- Magnetic Turbulence and Ion Dynamics in the Magnetotail.- Statistical Mechanics of Stable States Far from Equilibrium: Thermodynamics of Turbulent Plasmas.- Magnetic Field Line Transport in the Heliosphere and Energetic Particle Propagation from Corotating Interaction Regions to High Heliographic Latitudes.- Magnetic Field Line Transport in Anisotropic Magnetic Turbulence: Anomalous, Quasilinear, and Percolative Regimes Versus the Kubo Number.- Damping Effects on Parametric Decays of Alfvén Waves.- Radio Wave Propagation in the Corona and the Interplanetary Medium.- Summary of Session 1 : Fundamental Processes in Space Physics from Macroscopic to Microscopic Scales.- Some Physical Processes in Dusty Plasmas.- Shear Induced Phenomena in Dusty Plasma Flows.- Generation of Supercooled Strongly-Coupled Plasma by Artificial Injection into Space.- Supernovae Rayleigh-Taylor Instability Experiments on the CEA-Phébus Laser Facility.- A Simulation Method for Semicollisional Plasmas.- On the Magnetic Energy Avalanche in the Solar Atmosphere.- Hydrodynamics of the Solar Wind Expansion.- Kinetic Models of Solar and Polar Winds.- On the Exospheric Approach for the Solar Wind Acceleration.- Electron Temperature in the SolarWind from a Kinetic Collisionless Model: Application to High-Latitude Ulysses Observations.- Core, Halo and Strahl Electrons in the Solar Wind.- A Fokker-Planck Approach for the Expansion of the Fast Solar Wind: Why and How?.- Heliopause and Asteropauses.- Turbulence and Waves in the Solar Wind Formation Region and the Heliosphere.- Jets from Young Stars and Compact Objects Environments.- Radio Pulsars — What is to be Done.- Basics of Rotating Magnetospheres: Equilibrium and Stability.- The Physics and Chemistry of Sputtering by Energetic Plasma Ions.- The Atmosphere of Io: Abundances and Sources of Sulfur Dioxide and Atomic Hydrogen.- Two-Dimensional Non-Linear Alfvén Wings Generated by the Electrodynamic Interaction between Callisto and the Jovian Magnetosphere.- Magnetically-Driven Planetary Radio Emissions and Application to Extrasolar Planets.- Radio Observations of Ions in Comet Hale-Bopp.- Rapid Measurements of Solar Wind Ions with the Triana Plasmag Faraday Cup.- Quasi-Thermal Noise Diagnostics in Space Plasmas.- Quasi-Thermal Noise Spectra Measured by a Dipole Antenna in the Upper Hybrid Frequency Band.- Rosetta Mission Mutual Impedance Probe Modelling: The Short and Long Debye Length Plasma Cases.- Analytical Approach to Calculate Quasi-Thermal Noise Spectrum in Irregular Plasma.- Correlation Dependences Determined by Simultaneous Multispacecraft Observations of Solar Wind and IMF Structures.- Developments in Jovian Radio Emissions Tomography and Observations Techniques.- Radio Observations of Filaments at Metric and Decimetric Wavelengths.- Decametric Sounding of Near Earth Plasma: Correlation and Fractal Analysis of Scintillation Data.- The Heliosphere after Ullysses.- Major Unsolved Problems in Space Plasma Physics.- The Future of Space Science in the21st Century.- List of Participants.