<p> This thesis describes the development of an ultra low frequency digital analyzer from mathematical concepts and error characteristics set out in a publication^2 co-authored by the supervisor. The development is carried to the actual construction of a practical, economical, operating instrument, capable of giving information leading directly to the mean square value and the approximate amplitude probability distribution for ultra low frequency waveforms, both periodic and non-periodic. The final detailed design is described and justified, and the error characteristics derived in the above mentioned publication are interpreted for the design. No further development of principles or error characteristics is undertaken.</p> / Thesis / Master of Engineering (MEngr)

This thesis concerns the study of Ultra Low Frequency (ULF) waves during magnetospheric substorms. A wavelet algorithm which characterises magnetic ULF waves during substorm onset is presented. The algorithm is validated by comparing the spatial and temporal location of ULF wave onset to space-based observations of the aurora. It is demonstrated that the onset of ULF wave power expands coherently away from an ionospheric epicentre during the substorm expansion phase. Further, a case study of the time-domain causality of magnetotail plasma flows and ULF wave Pi2 pulsations is presented. Although highly correlated, it is demonstrated that the plasma flows cannot directly drive the ground magnetic waveforms but may be indirectly linked via a common source. Finally, results from a statistical study of ULF wave power during onset are presented. It is concluded that there is no statistical difference between historical sub-classifications of ULF waves observed during substorms.

No description available.

The effects of interplanetary shock impact angles have the potential to have far reaching consequences. By their nature, interplanetary shocks are a direct consequence of a variety of solar events including both Coronal Mass Ejections (CMEs) and Co-rotating Interaction Regions (CIRs). They have the ability to move the magnetopause, the boundary between the Earth's magnetosphere and the surrounding plasma, leading to ionospheric current systems and an enhanced ring current. Their association with a time-varying EMF also makes them potentially dangerous at a human level. This EMF can couple to electrical currents in technological infrastructure that can overload transformers, communication cables, and power grids. As IP shocks have the potential to have a large impact on our society, research to further our understanding of these events is prudent. We know that shocks can couple to currents and ULF waves in the magnetosphere-ionosphere system. Much of the current research into their behaviors has been focused on models and simulations and has indicated that the shock impact angle should affect the properties of the waves. To investigate the potential influence of the impact angle, data from a series of Antarctic magnetometers was collected and compared to a database of known interplanetary shocks to determine when the response to different shocks was detected at the magnetometer. For this investigation, we were concerned with determining what impact if any, the impact angle of the IP shock had on the generation of Pc5 waves. To that end, the power spectra both before and after the shock was calculated. This information was then combined with the shock impact angle to determine what effects if any, the shock impact angle had on Pc5 wave occurrence rates. From our research, it was determined that the impact angle of the interplanetary shock had a significant impact on the occurrence rate and properties of Pc5 waves observed by high-latitude ground magnetometers. / Master of Science / Interplanetary shocks, drive interactions between the solar wind and the Earth’s atmosphere, and they have the potential to have far reaching consequences. Caused by a variety of solar events including both Coronal Mass Ejections (CMEs) and Co-rotating Interaction Regions (CIRs), they have the ability to physically move the locations of regional boundaries of the ionized part of Earth’s atmosphere, leading to a variety of electromagnetic effects. They also pose a danger at the human level by generating electrical currents in technological infrastructure that can overload transformers, communication cables, and power grids. As they pose a danger to our society, understanding them is prudent. A large portion of the current research into their behaviors has been focused on models and simulations and has shown that the shock impact angle should affect the properties of the waves. For this investigation, data from a series of Antarctic sensors was collected and compared to a database of known interplanetary shocks to determine when different shocks were detected. Specifically, for our investigation, we were concerned with determining what impact if any, the impact angle of the IP shock had on the generation of Pc5 waves, a specific type of ULF wave. This was accomplished by calculating the power level at different frequencies both before and after the shock. This information was then combined with the shock impact angle to determine what effects if any, the shock impact angle had on Pc5 wave occurrence rates. From our research we found that the impact angle of the interplanetary shock had a significant impact on the generation of Pc5 waves.

Analisa-se no presente trabalho o problema das medidas de relaxação dielétrica a U.B.F. (Ultra Baixa Frequência). Propõe-se um modelo de ponte para tais medidas capaz de varrer o intervalo 10-3 Hz-10Hz, baseada na medida de fase conforme a discussão original de Van Turnhout e colaboradores. Analisa-se também os principais problemas experimentais com tal equipamento de U.B.F. e descreve-se a sua construção e funcionamento. Analisa-se também o modelo teórico de correlação entre medidas de U.B.F. e descarga de eletreto com correntes termo-estimulado. Em particular calculamos uma correção para a expressão integral dado por Van Turnhout e colaboradores que leva em conta a influência da energia de ativação na correlação entre as duas técnicas. Tal conversão é significante para valores da energia de ativação menor que 0,5eV e que ocorrem experimentalmente com frequência / In the present work we investigate the problem of U.L.F. (Ultra Low Frequency) dielectric relaxation. An experimental model is proposed for a bridge covering the range of 10-3Hz-10Hz, based on phase shift measurements originally proposed by Van Turhout and collaborators. We also analyze the main experimental problems with such U.L. F. measurements and describe its construction and performance. We have also investigated the theoretical correlation between U.L.F. dielectric relaxation and electret thermal stimulated currents. We calculate in particular, a correction for the integral expression given by Turnhout and collaborators that takes into account the value of the activation energy in the relation between the two techniques. The correction is important for values of the activation energy below 0,5eV, which occur frequently in dielectric relaxation processes

No presente trabalho descreve-se: a determinação da permitividade dielétrica complexa através de medidas de fase; a aplicação de técnicas de correlação e análise em séries de Fourier, para a determinação da fase, amplitude, qualidade e deformação do sinal atrasado; os circuitos eletrônicos do medidor de fase e do oscilador de U.B.F. programável; a programação desenvolvida em FORTRAN IV e MACRO-ASSEMBLER para o computador PDP 11/45, utilizado para operar o medidor de fase e o oscilador de U.B.F. / In the present work we describe: the determination of the complex dielectric permittivity by phase shift measurements; the application of correlation and Fourier series analyses to determine the phase shift, amplitude, quality and deformation of the shifted signal; the designed electronic hardware of the phase meter and programmb1e ultra-low frequency oscillator; the developed software written in FORTRAN IV and MACRO- ASSEMBLER for PDP 11/45, to operate the phase meter

Analisa-se no presente trabalho o problema das medidas de relaxação dielétrica a U.B.F. (Ultra Baixa Frequência). Propõe-se um modelo de ponte para tais medidas capaz de varrer o intervalo 10-3 Hz-10Hz, baseada na medida de fase conforme a discussão original de Van Turnhout e colaboradores. Analisa-se também os principais problemas experimentais com tal equipamento de U.B.F. e descreve-se a sua construção e funcionamento. Analisa-se também o modelo teórico de correlação entre medidas de U.B.F. e descarga de eletreto com correntes termo-estimulado. Em particular calculamos uma correção para a expressão integral dado por Van Turnhout e colaboradores que leva em conta a influência da energia de ativação na correlação entre as duas técnicas. Tal conversão é significante para valores da energia de ativação menor que 0,5eV e que ocorrem experimentalmente com frequência / In the present work we investigate the problem of U.L.F. (Ultra Low Frequency) dielectric relaxation. An experimental model is proposed for a bridge covering the range of 10-3Hz-10Hz, based on phase shift measurements originally proposed by Van Turhout and collaborators. We also analyze the main experimental problems with such U.L. F. measurements and describe its construction and performance. We have also investigated the theoretical correlation between U.L.F. dielectric relaxation and electret thermal stimulated currents. We calculate in particular, a correction for the integral expression given by Turnhout and collaborators that takes into account the value of the activation energy in the relation between the two techniques. The correction is important for values of the activation energy below 0,5eV, which occur frequently in dielectric relaxation processes

No presente trabalho descreve-se: a determinação da permitividade dielétrica complexa através de medidas de fase; a aplicação de técnicas de correlação e análise em séries de Fourier, para a determinação da fase, amplitude, qualidade e deformação do sinal atrasado; os circuitos eletrônicos do medidor de fase e do oscilador de U.B.F. programável; a programação desenvolvida em FORTRAN IV e MACRO-ASSEMBLER para o computador PDP 11/45, utilizado para operar o medidor de fase e o oscilador de U.B.F. / In the present work we describe: the determination of the complex dielectric permittivity by phase shift measurements; the application of correlation and Fourier series analyses to determine the phase shift, amplitude, quality and deformation of the shifted signal; the designed electronic hardware of the phase meter and programmb1e ultra-low frequency oscillator; the developed software written in FORTRAN IV and MACRO- ASSEMBLER for PDP 11/45, to operate the phase meter

The work assesses progress in the design of measuring workplace for measuring low level magnetic fields of low frequencies. The thesis describes the basic method of spreading of electromagnetic waves in free losslees ambience. Further is described effect with low level of ultra-low-frequency magnetic fields in the frequency band from 0.01 to 30 Hz for an individual or group of people and also the draft measuring methods for indicating or measuring changes in magnetic fields. Thesis deals with individual blocks of measuring workstation.

Presents results of research in the field of low-level electromagnetic fields interacting with the higher organisms, in the frequency band from 0,01 to 30 Hz effect on the individual or social group. Provides a description of the methodology of measuring and evaluating the impact of workplace assembled measuring low-level electromagnetic fields, extremely low frequency (ELF) on a sample of respondents. It was proposed measuring device for monitoring and evaluating how respondents' reactions to changes in the geomagnetic or external - external magnetic / electromagnetic field and to work for the measurement and evaluation of changes in external magnetic fields very low levels (ELF). This work is designed to process and evaluate implemented within experimental research into the influence of low-level magnetic fields in the Earth's resonator psychophysiological parameters of human organism and its behavior and decision-making. The work confirmed the influence of low-level magnetic fields on the psychophysiological parameters of the organism to be simultaneously confirmed the hypothesis established in accordance with the objectives of work.