Radio wave

About: Radio wave is a research topic. Over the lifetime, 14571 publications have been published within this topic receiving 167638 citations.

GPS Sounding of the Atmosphere from Low Earth Orbit: Preliminary Results

Abstract: This paper provides an overview of the methodology of and describes preliminary results from an experiment called GPS/MET (Global Positioning System/Meteorology), in which temperature soundings are obtained from a low Earth-orbiting satellite using the radio occultation technique. Launched into a circular orbit of about 750-km altitude and 70° inclination on 3 April 1995, a small research satellite, MicroLab 1, carried a laptop-sized radio receiver. Each time this receiver rises and sets relative to the 24 operational GPS satellites, the GPS radio waves transect successive layers of the atmosphere and are bent (refracted) by the atmosphere before they reach the receiver, causing a delay in the dual-frequency carrier phase observations sensed by the receiver. During this occultation, GPS limb sounding measurements are obtained from which vertical profiles of atmospheric refractivity can be computed. The refractivity is a function of pressure, temperature, and water vapor and thus provides informat...

Nonlinear phenomena in the ionosphere

Abstract: 1. Introduction.- 1.1 Data on the Structure of the Ionosphere.- 1.2 Features of Nonlinear Phenomena in the Ionosphere.- 1.2.1. Nonlinearity Mechanisms.- 1.2.2. Qualitative Character of Nonlinear Phenomena.- 1.2.3. Brief Historical Review.- 2. Plasma Kinetics in an Alternating Electric Field.- 2.1. Homogeneous Alternating Field in a Plasma (Elementary Theory).- 2.1.1.Electron Current-Electronic Conductivity and Dielectric Constant.- 2.1.2.Electron Temperature.- 2.1.3.Ion Current-Heating of Electrons and Ions.- 2.2. The Kinetic Equation.- 2.2.1. Simplification of the Kinetic Equation for Electrons.- 2.2.2. Transformation of the Electron Collision Integral.- 2.2.3. Inelastic Collisions.- 2.3. Electron Distribution Function.- 2.3.1. Strongly Ionized Plasma.- 2.3.2. Weakly Ionized Plasma.- 2.3.3. Arbitrary Degree of lonization-Concerning the Elementary Theory.- 2.4. Ion Distribution Function.- 2.4.1. Simplification of the Kinetic Equation.- 2.4.2. Distribution Function.- 2.4.3. Ion Temperature, Ion Current.- 2.5. Action of Radio Waves on the Ionosphere.- 2.5.1. lonization Balance in the Ionosphere.- 2.5.2. Effective Frequency of Electron and Ion Collisions-Fraction of Lost Energy.- 2.5.3. Electron and Ion Temperatures in the Ionosphere.- 2.5.4. Heating of the Ionosphere in an Alternating Electric Field.- 2.5.5.Perturbations of the Electron and Ion Concentrations.- 2.5.6. Artificial lonization of the Ionosphere-Heating of Neutral Gas.- 3. Self-Action of Plane Radio Waves.- 3.1. Simplification of Initial Equations.- 3.1.1. Nonlinear Wave Equation.- 3.1.2. Nonlinear Geometrical Optics of a Plane Wave.- 3.2. Effect of Nonlinearity on the Amplitude and Phase of the Wave.- 3.2.1. Self-Action of a Weak Wave.- 3.2.2. Self-Action of a Strong Wave.- 3.2.3. Self-Action of Waves in the Case of Artificial lionization.- 3.3. Change of Wave Modulation.- 3.3.1. Weak Wave.- 3.3.2. Change of Amplitude Modulation of Strong Wave.- 3.3.3. Phase Modulation.- 3.3.4. Nonlinear Distortion of Pulse Waveform.- 3.4. Generation of Harmonic Waves and Nonlinear Detection.- 3.4.1. Frequency Tripling.- 3.4.2. Nonlinear Detection.- 3.5. Self-Action of Radio Waves in the Lower Ionosphere.- 4. Interaction of Plane Radio Waves.- 4.1. Cross Modulation.- 4.1.1. Weak Waves.- 4.1.2. Strong Perturbing Wave.- 4.1.3. Resonance Effects near the Electron Gyrofrequency.- 4.2. Interaction of Unmodulated Waves.- 4.2.1. Interaction of Short Pulses.- 4.2.2. Change in the Absorption of a Wave Propagating in a Perturbed Plasma Region.- 4.2.3. Generation of Waves with Combination Frequencies.- 4.3. Radio Wave Interaction in the Lower Ionosphere.- 4.3.1. Cross Modulation.- 4.3.2. Fejer's Method.- 4.3.3. Nonstationary Processes in the Interaction of Strong Radio Waves.- 5. Self-Action and Interaction of Radio Waves in an Inhomogeneous Plasma.- 5.1. Inhomogeneous Electric Field in a Plasma.- 5.1.1. Fundamental Equations.- 5.1.2. Distribution of Density and Temperatures in Plasma.- 5.2. Kinetics of Inhomogeneous Plasma.- 5.2.1. Kinetic Coefficients. Elementary Theory.- 5.2.2. Kinetic Theory.- 5.2.3. Fully Ionized Plasma.- 5.3. Modification of the F Region of the Ionosphere by Radio Waves.- 5.3.1. Modification of the Electron Temperature and of the Plasma Concentration.- 5.3.2. Radio Wave Reflection Region.- 5.3.3. Growth and Relaxation of the Perturbations.- 5.4. Focusing and Defocusing of Radio Wave Beams.- 5.4.1. Nonlinear Geometrical Optics.- 5.4.2. Defocusing of Narrow Beams.- 5.4.3. Mutual Defocusing.- 5.4.4. Thermal Focusing in the Lower Ionosphere.- 6. Excitation of Ionosphere Instability.- 6.1. Self-Focusing Instability.- 6.1.1. Spatial Instability of a Homogeneous Plasma.- 6.1.2. Instability in the Wave-Reflection Region.- 6.2. Resonant Absorption and Resonance Instability.- 6.2.1. Langmuir Oscillations in an Inhomogeneous Plasma.- 6.2.2. Excitation of Plasma Waves.- 6.2.3. Resonance Instability.- 6.2.4. Absorption of Ordinary Radio Waves.- 6.3. Parametric Instability.- 6.3.1. Langmuir Oscillations of a Plasma in an Alternating Field.- 6.3.2. Parametric Excitation of Langmuir Oscillations.- 6.3.3. Parametric Instability in the Ionosphere.- 6.3.4. Dissipative Parametric Instability.