Search for dissertations about: "radio waves"
Showing result 1 - 5 of 51 swedish dissertations containing the words radio waves.
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1. Interaction between Electromagnetic Waves and Localized Plasma Oscillations
Abstract : This thesis treats interaction between electromagnetic waves and localized plasma oscillations. Two specific physical systems are considered, namely artificially excited magnetic field-aligned irregularities (striations) and naturally excited lower hybrid solitary structures (LHSS). READ MORE
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2. Radio waves in the ionosphere : Propagation, generation and detection
Abstract : We discuss various topics concerning the propagation, generation, and detec-tionof high-frequency (HF) radio waves in the Earth's ionosphere. With re-gardsto propagation, we derive a full wave Hamiltonian and a polarization evo-lutionequation for electromagnetic waves in a cold, stratified magnetoplasma. READ MORE
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3. VLF and ULF Waves Associated with Magnetospheric Substorms
Abstract : A magnetospheric substorm is manifested in a variety of phenomena observed both in space and on the ground. Two electromagnetic signatures are the Substorm Chorus Event (SCE) and Pi2 pulsations. The SCE is a Very Low Frequency (VLF) radio phenomenon observed on the ground after the onset of the substorm expansion phase. READ MORE
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4. Opening New Radio Windows and Bending Twisted Beams
Abstract : In ground based high frequency (HF) radio pumping experiments, absorption of ordinary (O) mode pump waves energises the ionospheric plasma, producing optical emissions and other effects. Pump-induced or natural kilometre-scale field-aligned density depletions are believed to play a role in self-focussing phenomena such as the magnetic zenith (MZ) effect, i. READ MORE
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5. Secondary Electromagnetic Radiation Generated by HF Pumping of the Ionosphere
Abstract : Electromagnetic waves can be used to transmit information over long distances and are therefore often employed for communication purposes. The electromagnetic waves are reflected off material objects on their paths and interact with the medium through which they propagate. READ MORE