Modulation Electric Field Intensity Sensor in a Conductive Medium

The requirement to conduct measurements across the big water areas and in the ocean depths arises a problem of creating devices to measure an electric field, being either set on the high-speed mobile carriers, or implemented as the sounders, which investigate a vertical or horizontal structure of the electric field of ocean. Manufactured, designed, and hypothetical devices for measuring poor electric fields of the ocean were analyzed. The analysis allowed us to prove that there is a need in creation of modulation sensors (with modulation of a non-electric origin) either with periodically changing capabilities of measuring bases, or with space-changing (and therefore, time-changing) position of measuring base of primary converters, as the most effective in terms of allocation and measurement of the modulated signal from unmodulated noise.The paper considers the mathematical models of modulation sensors of electric field intensity in the ultralow-frequency range, which are set on the mobile carriers. It justifies a choice of two basic models of primary converters with a change of the measuring base in space, i.e. with the "changing" base and with the "rotating" base. A feature of the offered models with vertical sounding is the minimum value of noise because of rotation of measuring electrodes in a magnetic field of Earth, and hydrodynamic noise. The paper shows that noise caused by the relative movement of sensor and water completely disappears in two cases:1. for a vertical sounder in the autonomous mode or a horizontal sounder with zero buoyancy in the specified shape of water;2. in a case when the sensor has no component of measuring base in the considered area, for example, for the sensor with in-line array of electrodes located in the horizontal plane.The paper proves advantage of the model with "rotating" measuring base, which provides the maximum power transfer from the primary converter to loading for all relative positions of an external electrode and contact orifice. For the sensor with "rotating" measuring base, it defines optimum, in terms of a maximum, power transferred to the matched loading, and ratios of its constructive sizes.</p

Multi-component electrode systems in geo-electric field intensity sensors for moving carriers

As an object of research, the electromagnetic field represents a set of parameters characterizing its electric and magnetic components. Methods and gages to measure the magnetic component of the Earth electromagnetic field are developed more explicitly than those for the electric one while an increasing need to measure the latter becomes of current importance when investigating the geodynamic activity in seismically dangerous regions by geo-electric methods. The experimental study of electric component of electromagnetic field in conducting media concerns the vector fields possessing E electric intensity. Generally, this is a three-dimensional field. The paper considers two- and three- component electrode systems in contact sensors of electric field intensity. The design of electrode systems most optimally meets requirements for devices to be set on mobile platforms for specific needs. It offers some designing aspects of evenly moved in conducting media sensors of alternating electric field for the frequencies in the range from units of Hz to tens of kHz. The feature of electrode systems is that the number of electrodes outnumbers the registered components of the electric field vector by one. Thus, nearly identical flow conditions in the vicinity of electrodes, geometric symmetry of the electrode system, and electric symmetry of measuring channels and, consequently, with no mutual influence of measuring channels at each other are provided. Using the task solutions of field theory the equivalent circuit parameters of primary converter of electrode sensor versus its geometrical sizes are defined. Optimum ratios of the geometrical sizes of primary converter are obtained. The offered criterion of optimization provides a maximum coefficient of transformation and sensitivity of measuring system. The paper considers an option of hardware implementation to measure the components of electric field intensity vector. The given results allow us to design symmetric multicomponent electrode systems for research of alternating electric fields, develop a circuit of their hardware implementation as applied to specific conditions of experiment. Practical research of such studies will allow to have more complete and reliable information about time-space anomalies of geoelectric field that, in turn, is necessary for research of the phenomena and the processes, from which such anomalies arise