These proceedings are based upon the invited review papers and the research notes presented at the NATO Advanced Research Institute on "Artificial Particle Beams in Space Plasma Studies" held at Geilo, Norway April 21-26, 1981. In the last decade a number of research groups have employed artificial particle beams both from sounding rockets and satellites in order to study various ionospheric and magnetospheric phenomena. However, the artificial particle beams used in this manner have given rise to a number of puzzling effects. Thus, instead of being just a probe for studying the ambient magnetosphere, the artificial particle beams have presented a rich variety of plasma physics problems, in parti~ular various discharge phenomena, which in themselves are worthy of a careful study. The experimental studies in space using artificial particle beams have in turn given rise to both theore tical and laboratory studies. In the laboratory experi ments special attention has been paid to the problem of creating spacelike conditions in the vacuum chamber. The theoretical. work has addressed the question of beam plasma-neutral interaction with emphasis on the wave generation and the modified energy distributions of the charged particles. Numerical simulations have been used extensively. With the advent of the Space Shuttle in which several artificial particle beam experiments are planned for the 1980's, there is a growing interest in such experiments. Furthermore, there is a need for coordinating these studies, both in space and in the laboratory.

Inhalt
1: Accelerator Experiments in Space.- The Use of Artificial Electron Beams as Probes of the Distant Magnetosphere.- Recent Observations of Beam Plasma Interactions in the Ionosphere and a Comparison with Laboratory Studies of the Beam Plasma Discharge.- Charged Particle Measurements from a Rocket-borne Electron Accelerator Experiment.- On the Use of Artificially Injected Energetic Electrons as Indicators of Magnetospheric Electric Fields Parallel to the Magnetic Lines of Force.- The French-Soviet Experiments ARAKS: Main Results.- Wave Excitation in Electron Beam Experiment on Japanese Satellite JIKIKEN (EXOS-B).- Plasma Waves and Electrical Discharges Stimulated by Beam Operations on a High Altitude Satellite.- Plasma Diagnostics by Electron Guns and Electric Field Probes on ISEE-1.- Stimulation of Plasma Waves by Electron Guns on the ISEE-1 Satellite.- Evidence for Beam-Stimulated Precipitation of High Energy Electrons.- Highlights of the Observations in the POLAR 5 Electron Accelerator Rocket Experiment.- Observations of Plasma Heating Effects in the Ionosphere by a Rocket-borne Electron Accelerator.- Plasma Waves Produced by the Xenon Ion Beam Experiment on the Porcupine Sounding Rocket.- The EXCEDE SPECTRAL Artificial Auroral Experiment: An Overview.- Onboard Radiometric Photography of EXCEDE SPECTRAL's Ejected Electron Beam.- General Discussion on Accelerator Experiments in Space.- 2: Natural Beam Plasma Interactions in Space.- Observations of Non-linear Processes in the Ionosphere.- Interaction between Natural Particle Beams and Space Plasmas.- 3: Accelerator Experiments in the Laboratory.- Laboratory Simulation of Injection of Particle Beams in the Ionosphere.- The NASA Space Environment Simulation Laboratory.- Visible Signatures of the Multi-stepTransition to a Beam-Plasma-Discharge.- Electron Energy Distribution Produced by Beam-Plasma-Discharge.- Time-dependent Plasma Behavior Trigged by a Pulsed Electron Gun under Conditions of Beam-Plasma-Discharge.- Ignition of the Beam-Plasma-Discharge and its Dependence on Electron Density.- Plasma Waves Stimulated by Electron Beams in the Lab and in the Auroral Ionosphere.- Studies of Beam-Plasma Interactions in a Space Simulation Chamber Using Prototype Space-Shuttle Instruments.- Transient Effects in Beam-Plasma Interactions in a Space Simulation Chamber Stimulated by a Fast Pulse Electron Gun.- Description of the Plasma Diagnostics Package (PDP) for the OSS-1 Shuttle Mission and JSC Plasma Chamber Test in Conjunction with the Fast Pulse Electron Gun (FPEG).- Radial Dependence of HF Wave Field Strength in the BPD Column.- Laboratory Beam-Plasma Interactions Linear and Nonlinear.- Electromagnetic Radiation from Beam-Plasma Instabilities.- Electron Beam Injection and Associated Phenomena as Observed in a Large Space Simulation Chamber.- General Discussion on Accelerator Experiments in the Laboratory.- 4: Theoretical Aspects of The Beam Plasma Interactions.- Theory of Beam Plasma Discharge.- Electron Beam as a Source of Electrostatic Waves.- Spontaneous Emission of a Charged Particle Beam Inside a Plasma: Coherent and Incoherent Aspects.- The Beam-Plasma Discharge under Space-like Conditions.- Plasma Waves Generated by Rippled, Magnetically Focused Electron Beams Surrounded by Tenuous Plasmas.- 5: Neutralization of a Charged Body in Space.- Charge Neutralization as Studied Experimentally and Theoretically.- Experimental Studies of the Neutralization of a Charged Vehicle in Space and in the Laboratory in Japan.- Electric Field Observations of Time Constants Relatedto Charging and Charge Neutralization Processes in the Ionosphere.- Measurements of Vehicle Potential Using a Mother-Daughter Tethered Rocket.- General Discussion on Neutralization of a Charged Body in Space.- 6: Future Plans.- Space Experiments with Particle Accelerators (SEPAC).- The Norwegian Program Using Particle Accelerators in Space.- The Artificially Injected Charged Particles as a Tool for the Measurement of the Electric Field in the Magnetosphere.- General Discussion on Future Experiments.- Participants.