Plasma Instabilities
Mostrando 1-12 de 15 artigos, teses e dissertações.
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1. Surface-wave instabilities in a plasma rotating with step-like frequency profile
An approach for the theory of nonlocal magnetorotational and convective instabilities in a rotating plasma is developed, on the basis of the surface wave concept, which allows the derivation of useful analytical results.It is assumed that the rotation frequency has a step-like profile, so that a narrow transition layer separates two regions with different ro
Brazilian Journal of Physics. Publicado em: 2009-03
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2. Simulação computacional de emissões eletromagnéticas em plasmas espaciais / Computational simulation of electromagnetic emission in space plasmas
Atualmente sabemos que feixes de elétrons desempenham um importante papel no mecanismo de emissões de rádio que são comumente observadas na região acima do arco de choque terrestre e explosões solares tipo II e III. Feixes de elétrons que são injetados de volta no vento solar, a partir do arco de choque terrestre, são uma possível fonte das ondas d
Publicado em: 2008
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3. Simulação computacional de emissões eletromagnéticas em plasmas espaciais / Computational simulation of electromagnetic emission in space plasmas
Atualmente sabemos que feixes de elétrons desempenham um importante papel no mecanismo de emissões de rádio que são comumente observadas na região acima do arco de choque terrestre e explosões solares tipo II e III. Feixes de elétrons que são injetados de volta no vento solar, a partir do arco de choque terrestre, são uma possível fonte das ondas d
Publicado em: 2008
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4. Estudo de irregularidades ionosféricas em períodos de baixa ocorrência em baixas latitudes sob condições calmas / Studies of low-latitude ionospheric irregularities during the periods of their low frequency of occurrence, and under quiet conditions
This thesis research focalises a study of the mechanisms involved in the generation and evolution of the ionospheric plasma bubbles by means of experimental data and modeling. The experimental data were obtained by night airglow (OI630nm) imagers and Digisondes. The airglow allsky imager was located at São João do Cariri (7,5°S, 36,5°O, I=-20°), and the
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 30/11/2005
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5. Studies of low-latitude ionospheric irregularities during the periods of their low frequency of occurrence, and under quiet conditions / Estudo de irregularidades ionosféricas em períodos de baixa ocorrência em baixas latitudes sob condições calmas
This thesis research focalises a study of the mechanisms involved in the generation and evolution of the ionospheric plasma bubbles by means of experimental data and modeling. The experimental data were obtained by night airglow (OI630nm) imagers and Digisondes. The airglow allsky imager was located at São João do Cariri (7,5°S, 36,5°O, I=-20°), and the
Publicado em: 2005
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6. Estudo de irregularidades ionosféricas em períodos de baixa ocorrência em baixas latitudes sob condições calmas / Studies of low-latitude ionospheric irregularities during the periods of their low frequency of occurrence, and under quiet conditions
Esta dissertação apresenta um estudo dos mecanismos de geração e evolução das instabilidades ionosféricas que geram as bolhas ionosféricas. Através de dados obtidos de imageadores e digissondas, localizados em São João do Cariri (imageador allsky 7,5°S, 36,5°O, I=-20°), em São Luís (digissonda 2,6°S, 44,2°O, I=-2°), Fortaleza (digissonda 3
Publicado em: 2005
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7. Electron Cyclotron Emission in the TCABR Tokamak: An Experimental Study. / "Emissão Eletrociclotrônica no Tokamak TCABR: Um Estudo Experimental"
In this work, an experimental study of the Electron Cyclotron Emission (ECE) in the TCABR Tokamak, is described. An ECE sweeping heterodyne radiometer, operating in the 50-85 GHz frequency range, was installed, calibrated and used to detect ECE radiation in the second harmonic extraordinary mode from thermal plasma discharges. The noise temperature, amplitud
Publicado em: 2005
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8. Behavior of linear beam-plasma instabilities in the presence of finite amplitude circularly polarized waves
We review the effect of finite amplitude circularly polarized waves on the behavior of linear ion-beam plasma instabilities. It has been shown that left-hand polarized waves can stabilize linear right-handed instabilities [1]. It has also been shown that for beam velocities capable of destabilizing left-handed waves, left-hand polarized large amplitude waves
Brazilian Journal of Physics. Publicado em: 2004-12
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9. Editorial
Publicado em: 2004
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10. {Kinetic simulations to modeling events in space plasmas} / Simulação cinéticas para modelagens de fenômenos em plasma espaciais
- The purpose of this doctoral thesis is to study some phenomena in space plasma using theoretical models and computer simulation via particles. Firstly, we concentrate on studying the process involving nonlinear interactions among Langmuir, electromagnetic and ion acoustic waves, associated with type III solar radio bursts. Starting from the generalized Zak
Publicado em: 2004
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11. Control of chaotic magnetic fields in tokamaks
Chaotic magnetic field lines play an important role in plasma confinement by tokamaks. They can either be generated in the plasma as a result of natural instabilities or artifficially produced by external conductors, like resonant helical windings and ergodic magnetic limiters. This is a review of works carried out at the Universidade de São Paulo and Unive
Brazilian Journal of Physics. Publicado em: 2002-12
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12. Effect of the vacuum vessel on the measurements of mirnov oscillation in TCABR
Magnetic field due to instabilities in plasma is expected to be reflected in the conductive vessel wall. We evaluate the reflection effect in the Brazilian tokamak TCABR. The magnetic field due to the plasma is represented by a toroidal harmonic function in vacuum and the reflected field is written as a series of harmonic functions in vacuum, generated in th
Brazilian Journal of Physics. Publicado em: 2002-03