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Past, Present and Future of Active Experiments in Space

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Past, Present and Future of Active Experiments in Space PAST, PRESENT AND FUTURE OF ACTIVE EXPERIMENTS IN SPACE A. V. Streltsov1,2, J.-J. Berthelier3, A. A. Chernyshov4, V. L. Frolov5,6, F. Honary7, M. J. Kosch7,8,9, R. P. McCoy10, E. V. Mishin2, M. T. Rietveld11,12 1Embry-Riddle Aeronautical University, Daytona Beach, Florida, USA; 2Air Force Research Laboratory, Space Vehicles Directorate, Albuquerque, New Mexico, USA; 3LATMOS/IPSL, CNRS-UPMC-UVSQ, UPMC, Paris, France; 4Space Research Institute, Moscow, Russia; 5Nizhny Novgorod State University, Nizhny Novgorod, Russia; 6Kazan Federal University, Kazan, Russia; 7Lancaster University, Lancaster, United Kingdom; 8South African National Space Agency, Hermanus, South Africa; 9University of the Western Cape, Bellville, South Africa; 10Geophysical Institute, University of Alaska Fairbanks, Fairbanks, Alaska, USA; 11EISCAT, Ramfjordbotn, Norway; 12UiT The Arctic University of Norway, Tromsø, Norway. Abstract. Active ionospheric experiments using high-power, high-frequency transmitters, “heaters”, to study plasma processes in the ionosphere and magnetosphere continue to provide new insights into understanding plasma and geophysical proceses. This review describes the heating facilities, past and present, and discusses scientific results from these facilities and associated space missions. Phenomena that have been observed with these facilities are reviewed along with theoretical explanations that have been proposed or are commonly accepted. Gaps or uncertainties in understanding of heating initiated phenomena are discussed together with proposed science questions to be addressed in the future. Suggestions for improvements and additions to existing facilities are presented including important satellite missions which are necessary to answer the outstanding questions in this field. 1 Table of Contents 1 Introduction.............................................................................................................................................. 4 2 Experimental Facilities ............................................................................................................................ 6 2.1 Ground Facilities .............................................................................................................................. 6 2.1.1 HAARP ...................................................................................................................................... 7 2.1.2 SURA ......................................................................................................................................... 8 2.1.3 EISCAT ................................................................................................................................... 10 2.1.4 Arecibo .................................................................................................................................... 13 2.1.5 Science Topics ......................................................................................................................... 15 2.2 Satellites .......................................................................................................................................... 16 2.2.1 DEMETER Satellite ................................................................................................................ 18 2.2.2 Defense Meteorological Satellite Program (DMSP)................................................................ 20 2.2.3 The Demonstration and Science Experiments (DSX) Satellite ............................................... 22 2.2.4 RESONANCE Satellite ........................................................................................................... 24 3 Theory of the HF Ionospheric Modification .......................................................................................... 29 3.1 Propagation of O-Mode Waves ...................................................................................................... 30 3.2 Electrostatic Plasma Waves ............................................................................................................ 31 3.2.1 Wave-Particle Analogy ............................................................................................................ 33 3.3 Ponderomotive Parametric Instability (PPI) ................................................................................... 33 3.3.1 PPI in Isotropic Plasma (PPIL) ................................................................................................. 35 3.3.2 Parametric Decay Instability (PDIL) ........................................................................................ 36 3.3.3 Modulational Instability (MI) .................................................................................................. 36 3.4 PPI in the Plasma Resonance Layer ............................................................................................... 37 3.4.1 Strong Langmuir Turbulence (SLT) ........................................................................................ 38 3.4.2 Coexistence of WT and SLT Regimes .................................................................................... 40 3.4.3 Full-Wave Simulations of SLT at HAARP ............................................................................. 41 O 3.5 PPI in the Upper Hybrid Layer (PPI UH / EB ) .................................................................................... 42 3.5.1 Upper Hybrid PPI .................................................................................................................... 43 3.5.2 Langmuir Turbulence in the UH Layer ................................................................................... 45 3.5.3 Lower Hybrid PPI .................................................................................................................... 45 3.6 Nonlinear Thermal Effects.............................................................................................................. 46 3.6.1 Electron Heating and Thermal Flux......................................................................................... 47 3.6.2 Thermal Self-Focusing Instability (TSFI) ............................................................................... 48 3.6.3 Thermal Parametric Instability (TPI) ....................................................................................... 48 3.7 Electron Acceleration ..................................................................................................................... 51 4 Active Experiments ............................................................................................................................... 53 4.1 Stimulated Electromagnetic Emissions (SEEs) .............................................................................. 53 4.2 Artificial Field-Aligned Irregularities (FAIs) ................................................................................. 60 4.2.1 Amplitude-Time History of the Pump Wave Reflected from the Ionosphere ......................... 64 2 4.2.2 Temporal Development of FAIs .............................................................................................. 66 4.2.3 Relaxation of FAIs ................................................................................................................... 67 4.2.4 Temporal Evolution of Short-Pulse Pumped FAIs .................................................................. 67 4.2.5 Spectral Characteristics of SSIs ............................................................................................... 68 4.2.6 Dependence of FAI Intensity on the Pump Power .................................................................. 70 4.2.7 Magnetic Zenith Effects .......................................................................................................... 70 4.2.8 Unexplained UHF Radar Backscatter at the Magnetic Zenith ................................................. 72 4.2.9 Gyroharmonic Effects Associated with FAIs .......................................................................... 73 4.2.10 Concluding Remarks ................................................................................................................ 76 4.3 Ducts ............................................................................................................................................... 77 4.3.1 DEMETER Observations over SURA ..................................................................................... 78 4.3.2 DMSP and DEMETER Observations over HAARP ............................................................... 80 4.3.3 Numerical Modeling of Artificial Ducts .................................................................................. 81 4.4 Optical Emissions ........................................................................................................................... 82 4.4.1 Artificial Aurora ...................................................................................................................... 82 4.4.2 Electron Temperature Effects .................................................................................................. 85 4.4.3 Magnetic Aspect Angle Effects ............................................................................................... 87 4.4.4 Electron Energy Spectrum ....................................................................................................... 87 4.4.5 Small-Scale Optical Structures ...............................................................................................
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