Measurement Of DC Electric Fields Research Articles

Establishment of DC Electric Field Measurements by Linear Dipole Type Sensor System

Nowadays, electric fields above the ground are measured mainly by so‐called ‘field mill type’ sensor systems. However, their measurements are limited to vertical field component only due to its technical constraint. Out of necessity of measurements of electric field components in arbitrary directions in any spaces, a linear dipole type DC electric field sensor system, which can be immersed within a fully uniform electric field, was developed. However, it had been remained unknown whether its sensor output is parameter‐dependent or not, and unknown whether it can provide reliable intensity value of measured electric fields or not. In order to clarify these points, test observations of natural electric fields have been conducted by means of plural sensor systems having different values of parameter. Obtained electric field intensity derived from the observed data has shown a parameter‐dependence despite that it should be constant for any parameter values. After a detailed analysis of the effect of the parameter along the equivalent electric circuit of the sensor system, a field‐calibrating formula, which can make the sensor system to be parameter‐independent, has been found. Finally, the linear dipole type DC electric field sensor system for obtaining reliable electric field intensities has been established. © 2024 The Author(s). IEEJ Transactions on Electrical and Electronic Engineering published by Institute of Electrical Engineers of Japan and Wiley Periodicals LLC.

Electric field control of magnetization in polycrystalline ZnO film

A polycrystalline ZnO film is grown on a silicon substrate by the pulsed laser deposition method, and the electric field-induced magnetization in ZnO using an optical cantilever beam magnetometer setup is studied. The magnetization vs bipolar dc electric field measurements reveal the occurrence of magnetization switching in the ZnO film. The magnetization switching in the presence of an electric field is ascribed to the converse magnetoelectric (ME) coupling that takes place between the electrical and the magnetic order parameters existing in the ZnO film. We have found the strain-driven magnetization change as evidenced by the butterfly shape of the magnetization vs the electric field curve. A saturation magnetization of 13.31 MA/m is obtained. Moreover, a significant value of the ME coupling coefficient (α) (1.61 × 10−7 s/m) has also been reported in this article. The emergence of electric field-induced magnetization in a single polycrystalline ZnO film is regarded to be a very promising aspect in designing high-density energy-efficient spintronic and different multifunctional devices.

Measurement of dc and ac Electric Fields inside an Atomic Vapor Cell with Wall-Integrated Electrodes

We present and characterize a Rb atomic vapor cell with silicon-ring electrodes embedded between borosilicate glass tubes. The ring electrodes can be externally connectorized for application of electric fields to the inside of the cell. An atom-based, all-optical, laser-spectroscopic field-sensing method is employed to measure electric fields in the cell. Here, the Stark effect of electric-field-sensitive rubidium Rydberg atoms is exploited to measure dc electric fields in the cell of approximately $5$ V/cm, with a relative uncertainty of 10%. Measurement results are compared with dc field calculations, allowing us to quantify electric field attenuation due to free surface charges inside the cell. We further measure the propagation of microwave fields into the cell, using Autler-Townes splitting of Rydberg levels as a field probe. Results are obtained for a range of microwave powers and polarization angles relative to the cell's ring electrodes. We compare the results with microwave-field calculations.

Electrometry of a single resonator mode at a Rydberg-atom–superconducting-circuit interface

The electric-field distribution in a single mode of a $\ensuremath{\lambda}/4$ superconducting coplanar waveguide (CPW) microwave resonator has been probed using beams of helium Rydberg atoms. In the experiments the atoms were prepared in the $1\mathrm{s}55\mathrm{s}{\phantom{\rule{0.16em}{0ex}}}^{3}{\mathrm{S}}_{1}$ Rydberg level by laser photoexcitation. They then traveled over the CPW resonator that was fabricated on a NbN superconducting chip operated at 3.8 K. The resonator was driven at its third-harmonic frequency, near resonant with the two-photon $1\mathrm{s}55\mathrm{s}{\phantom{\rule{0.16em}{0ex}}}^{3}{\mathrm{S}}_{1}\ensuremath{\rightarrow}1\mathrm{s}56\mathrm{s}{\phantom{\rule{0.16em}{0ex}}}^{3}{\mathrm{S}}_{1}$ transition at ${\ensuremath{\omega}}_{55\mathrm{s},\phantom{\rule{0.16em}{0ex}}56\mathrm{s}}/2=2\ensuremath{\pi}\phantom{\rule{0.16em}{0ex}}\ifmmode\times\else\texttimes\fi{}\phantom{\rule{0.16em}{0ex}}19.556\phantom{\rule{0.16em}{0ex}}499$ GHz. The coherence times of the atom--resonator-field interaction were determined at selected locations above the resonator by time-domain measurements of Rabi oscillations and found to be up to $0.8\phantom{\rule{0.16em}{0ex}}\ensuremath{\mu}\mathrm{s}$ for Rabi frequencies of $\ensuremath{\sim}2\ensuremath{\pi}\phantom{\rule{0.16em}{0ex}}\ifmmode\times\else\texttimes\fi{}\phantom{\rule{0.16em}{0ex}}3$ MHz. The coherence times of the atomic superposition states, generated following the interaction of the atoms with the microwave field in the resonator, were inferred from high-resolution cavity-enhanced Ramsey spectra to be $\ensuremath{\sim}2.5\phantom{\rule{0.16em}{0ex}}\ensuremath{\mu}\mathrm{s}$. These Ramsey spectra also allowed the measurement of residual uncanceled dc electric fields of $26.6\ifmmode\pm\else\textpm\fi{}0.6$ mV/cm at the position of the atoms $\ensuremath{\sim}300\phantom{\rule{0.16em}{0ex}}\ensuremath{\mu}\mathrm{m}$ above the surface of the superconducting chip. These results represent an essential step toward applications of hybrid systems, comprising Rydberg atoms coherently coupled to superconducting microwave circuits, in quantum optics and quantum information processing.

Thermospheric Neutral Winds as the Cause of Drift Shell Distortion in Earth’s Inner Radiation Belt

Recent analysis of energetic electron measurements from the Magnetic Electron Ion Spectrometer instruments onboard the Van Allen Probes showed a local time variation of the equatorial electron intensity in the Earth’s inner radiation belt. The local time asymmetry was interpreted as evidence of drift shell distortion by a large-scale electric field. It was also demonstrated that the inclusion of a simple dawn-to-dusk electric field model improved the agreement between observations and theoretical expectations. Yet, exactly what drives this electric field was left unexplained. We combine in-situ field and particle observations, together with a physics-based coupled model, the Rice Convection Model (RCM) Coupled Thermosphere-Ionosphere-Plasmasphere-electrodynamics (CTIPe), to revisit the local time asymmetry of the equatorial electron intensity observed in the innermost radiation belt. The study is based on the dawn-dusk difference in equatorial electron intensity measured at L = 1.30 during the first 60 days of the year 2014. Analysis of measured equatorial electron intensity in the 150–400 keV energy range, in-situ DC electric field measurements and wind dynamo modeling outputs provide consistent estimates of the order of 6–8 kV for the average dawn-to-dusk electric potential variation. This suggests that the dynamo electric fields produced by tidal motion of upper atmospheric winds flowing across Earth’s magnetic field lines - the quiet time ionospheric wind dynamo - are the main drivers of the drift shell distortion in the Earth’s inner radiation belt.

Optical DC electric field sensing based on the Pockels effect using bismuth germanate crystals.

The measurement of DC electric fields faces problems such as space charge accumulation and difficulties in distinguishing the DC signal from the output signal. Therefore, a novel, to the best of our knowledge, optical electric field sensor based on the Pockels effect is proposed to measure DC electric fields using a rotating bismuth germanate crystal. Theoretical derivation and signal optimization are performed to eliminate the influence of space charge accumulation on the DC electric field measurement. The measurement results show that the proposed optical electric-field sensor is suitable for the accurate measurement of DC electric fields, and the precision error is within ±0.1%.

Research and Design of Rotary Optical Electric Field Sensor

In order to solve the problem that traditional optical electric field sensors are susceptible to temperature, charge drift and other internal and external factors in the measurement of DC electric field and ultra-low frequency electric field, an optical electric field sensor with rotating structure is proposed. The mathematical model of the output signal of the sensor is theoretically analyzed and deduced, and the structural design scheme of the sensor is given, and the experimental verification is carried out. The simulation analysis and experimental verification results show that the rotating optical electric field sensor has good linearity, and can improve the measurement accuracy and stability of the sensor when measuring DC electric field and ultra-low frequency electric field.

Measuring AC/DC hybrid electric field using an integrated optical electric field sensor

Measuring the AC and DC hybrid electric field is significant for the electromagnetic environment evaluation and for the design of AC/DC hybrid transmission lines. In this paper, a measuring method for both DC and AC electric field measurement by the integrated optical electric field sensor was proposed. The DC electric field can be measured by rotating the sensor by a servomotor which modulates the DC signals into AC signals. A measuring system was implemented and calibrated. A field measurement under an AC/DC hybrid transmission line in Jeju Island, Korea was carried out, and the measured data of the electric field under different DC operating modes were obtained. The results obtained by the proposed method were in reasonably good agreement with a commercial AC probe and the computed DC electric field.

Shorting Factor In-Flight Calibration for the Van Allen Probes DC Electric Field Measurements in the Earth's Plasmasphere.

Satellite-based direct electric field measurements deliver crucial information for space science studies. Yet, they require meticulous design and calibration. In-flight calibration of double-probe instruments is usually presented in the most common case of tenuous plasmas, where the presence of an electrostatic structure surrounding the charged spacecraft alters the geophysical electric field measurements. To account for this effect and the uncertainty in the boom length, the measured electric field is multiplied by a parameter called the shorting factor (sf ). In the plasmasphere, the Debye length is very small in comparison with spacecraft dimension and there is no shorting of the electric field measurements (sf = 1). However, the electric field induced by spacecraft motion greatly exceeds any geophysical electric field of interest in the plasmasphere. Thus, the highest level of accuracy in calibration is required. The objective of this work is to discuss the accuracy of the setting Sf =1 and therefore to examine the accuracy of Van Allen Probes electric field measurements below L = 2. We introduce a method to determine the shorting factor near perigee. It relies on the idea that the value of the geophysical electric field measured in the Earth's rotating frame of reference is independent of whether the spacecraft is approaching perigee or past perigee, i.e. it is independent of spacecraft velocity. We obtain that Sf =0.994 ± 0.001. The resulting margins of errors in individual electric drift measurements are of the order of ± 0.1% of spacecraft velocity (a few meters per second).

Magnetic and tunable dielectric properties of DyCrO3 thin films

DyCrO3 (DCO) belongs to the family of rare-earth chromites, some members of which exhibit magnetoelectric multiferroic properties. This work characterizes the dielectric tunability in DCO, which is typically, for conventional ferroelectrics, found to maximize near the ferroelectric to paraelectric transition. Two films of DCO were fabricated via a hybrid solution synthesis route on different substrates: one on single crystalline (001) LaAlO3 (LAO) and the other on (001) LAO coated with a conducting LaNiO3 (LNO) layer. The synthesis method resulted in films with both out-of-plane and in-plane texture in the DCO. The lattice mismatch strain between film and substrate caused a slight increase in the Neel temperature of the DCO film on LAO. Transmission electron microscopy images of the DCO film on the LNO/LAO revealed the epitaxial relationship between these phases. The temperature dependence of the relative permittivity showed diffused transition and a frequency dispersion similar to what is observed in typical relaxor ferroelectrics. Isothermal dielectric constant versus dc electric field measurements showed an electric field tunable relative permittivity (i.e., tunability). This tunability reached a broad plateau near the Neel temperature. Such maxima in dielectric tunability are typically observed near a ferroelectric–paraelectric transition, and its proximity to the magnetic ordering temperature in DCO indicates magnetically driven ferroelectricity in this material.

Research on a Novel MEMS Sensor for Spatial DC Electric Field Measurements in an Ion Flows Field.

Thus far, despite the development of electric field sensors (EFSs) such as field mills, optoelectronic EFSs and microelectromechanical system (MEMS)-based EFSs, no sensor can accurately measure an electric field in space due to the existence of space charge and the influence of charge attachment. To measure a spatial synthetic electric field in an ion flow field, a double potential independent differential EFS based on MEMS is proposed. Compared with other EFSs, this method has the advantages of independent potential (without grounding) and the ability to support the measurement of the synthetic ion flow electric field in space. First, to analyse the charge distribution after the sensor is involved exposed to an electric field, a simulation model was constructed. Then, given the redistribution of the spatial electric field in space and the influence of the surface charge on the sensor, the quantitative relationship between the electric field to be measured and that measured by the proposed sensor was obtained. To improve the performance of the EFS, a set of synthetic field strength sensor calibration systems that consider spatial ion flow injection was established. Furthermore, the parameter λ, which is related to the relative position of the differential chips, was determined. Finally, a series of comparative experiments indicated that the differential EFS highlighted in the present study exhibits good linearity and accuracy.

Methods to reduce errors for DC electric field measurement in oil-pressboard insulation based on Kerr-effect

Kerr-effect based methods show great potential for the measurement of electric field in liquid dielectric. However, the accuracy of the Kerr-effect based measurement over the DC electric field in oil-pressboard insulation remains to be a challenge. With the establishment of a Kerr-effect based non-contact and real-time electric field measurement system, the present paper analyzes the factors causing the measurement errors and thus proposes the countermeasures accordingly. It is indicated that the measurement errors resulted from the edge effect generated by electrode and pressboard could be reduced to 1.3% by lengthening the electrode, shortening the spacing distance between the electrode and the test chamber, and providing the electrode covering. The errors caused by non-ideal characteristics of the optical devices could be adjusted through the calibration of its parameters. The errors caused by the noise from laser source could be reduced to 0.86% for DC electric field and 1.6% for AC electric field through suitable selection of AC modulation frequency as 1310 Hz, which could also improve the signal-to-noise ratio. The test results conclude that the measurement system established under the present research could accurately measure DC electric field of 20 V/mm with the error being smaller than 5.4%.

Impact factors in calibration and application of field mill for measurement of DC electric field with space charges

The DC electric field is sometimes accompanied by space charges caused by the partial discharge in the air, which impacts DC electric field measurements. This paper describes the impact factors in the calibration and application of the field mill for measuring the DC electric field with space charges. First, the influence of the space charges on calibration results is evaluated and discussed. Then, both the impact of the height of the meter probe above the ground and the touch resistance between the ground and the meter on the measurement results are investigated. Correct calibration and application methods are presented. The results are expected to be of use to engineers for conducting accurate measurements of the DC electric field with space charges.

The Measurement of DC Electric Field for Transformer Oil System Based on the Kerr Electro-Optic Effect

This study presents a effective approach for the measurement of electric field in liquid dielectric with small Kerr constant based on the principle of Kerr electro-optic effect. In the paper, the distribution of electric field in transformer oil is measured of different electrode materials below 30KV. According to experiments it can be concluded that the intensity of light corresponds with the electric field between the two parallel-plane electrodes in test cell in a certain range of the voltage applied. The conclusion reveals that the distribution and variation tendency of the electric field between the two electrodes can be drawn by the analysis of the light intensity.

Ram/Wake and Surface Layer Effects on DC Electric Field Measurements in LEO

The USAF Communication/Navigation Outage Forecast System satellite, launched into an eccentric low earth orbit (401 km perigee by 867 km apogee) of 13° inclination on April 16, 2008, has a set of dc electric field probes that constitute part of the Vector Electric Field Investigation (VEFI). In order to obtain the ambient electric field, the v×B component of electric field must be subtracted from the VEFI measurements. After this subtraction and the subtraction of the ambient dc electric components, a residual dc offset directed toward the spacecraft wake is still observed, which varies somewhat within an orbit and on longer timescales. One of the interesting features of these offsets is that when the satellite is occasionally rotated, the offsets are reset to their baseline values, only to come back within a month or so. Various hypotheses have been proposed to explain the residual dc offsets. In this paper, we explore the possibilities that either the influence of the spacecraft wake on the sensors or that modified surface layers on the probe surfaces are producing the offsets. Nascap-2k and EWB models are used to show the various influences of the wake and of surface materials. Finally, a hypothesis is produced that quantitatively explains many of the salient features of the offsets. The feasibility of using dc electric field probes in space is reaffirmed. Recommendations for probe construction on future spacecraft to ameliorate spurious effects are presented.

Experimental Analysis and Numerical Simulation of the Operation of the DEMETER Electric Field Instrument in Deep Equatorial Plasma Depletions

The development of deep plasma depletions in the equatorial ionosphere at time of magnetic storms is of particular interest in space and plasma physics as well as in the field of radio communications. Detailed plasma, dc electric field, and wave observations were performed by the Detection of Electro-Magnetic Emissions Transmitted from Earthquake Regions microsatellite through several depletions where the large Debye length may lead to significant disturbances on the measurements of dc electric fields by the double probe instrument. After an overview of the data acquired in a well-developed plasma cavity, we present a numerical simulation study that was undertaken to model the operation of the electric field probes in their actual environment. The initial results indicate that, in low-density ionospheric plasma and depending on the potential difference between the probes and the boom, non negligible errors may arise from the influence of the boom on the probe current collection.

대지전계 측정을 위한 필드밀의 설계 및 제작

A field mill capable of measuring the magnitude and polarity of electric fields at the ground level was studied to apply to a lightning warning system as a sensor. We designed and fabricated a planar-shutter type field mill with a rotating-vanes. A calibration of the field mill was performed in a vertically symmetrical arrangement which consists of two equal size parallel round plates to form a homogeneous electrical fields. The sensitivity of the field mill was adjusted at 0.5[V/kV/m], and this covers a ranges from 200[V/m] to 20[kV/m]. After the calibration experiment, the field mill was installed on the roof of a building to measure the changes of electric field intensity caused by thunderclouds. During the period from July 1. 2006 to July 15. 2006, the electric field intensity was recorded a ranges of depending on generation, extinction and movement of thunderclouds. From the actual test on the ground it is confirmed that the field mill has a good performance necessary for the measurement of DC electric fields.

Possibilities for measurement and compensation of stray DC electric fields acting on drag-free test masses

DC electric fields can combine with test mass charging and thermal dielectric voltage noise to create significant force noise acting on the drag-free test masses in the Laser Interferometer Space Antenna (LISA) gravitational wave mission. This paper proposes a simple technique to measure and compensate average stray DC potentials at the mV level, yielding substantial reduction in this source of force noise. We discuss the attainable resolution for both flight and ground based experiments.

Validation of electro-optic sensors for measurement of DC fields in the presence of space charge

The paper presents theoretical analysis and experimental verification of an electro-optic sensor for measurements of DC electric fields in space charge environment. Effects of both unipolar and bipolar charge were investigated. It was shown that in both cases the sensor output is linearly dependent on the intensity of measured electric field and independent of the space charge density. The achieved measurement resolution is 100 V/m with a dynamic range of 80 dB and a temperature stability of 0.1%/°C for temperatures near 20 °C.

Evaluation of DC electric field measurement by the double probe system aboard the Geotail spacecraft

We summarize the characteristics of the DC electric field measurement by the double probe system, PANT and EFD-P, aboard Geotail. The accuracy and correction factors for the gain (effective length) and off-set, which depends on ambient plasma conditions are provided.