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We report on development of a ground-based bi-axial Search-Coil Magnetometer (SCM) designed to measure time-varying magnetic fields associated with magnetosphere-ionosphere coupling processes. The instrument provides two-axis magnetic field wave vector data in the Ultra Low Frequency or ULF (1 mHz to 5 Hz) range. ULF waves are well known to play an...
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... have long been used for ground-based observa- tions of geomagnetic pulsations. The two search-coil magnetic sensors are identical and assembled orthogonally (X and Y axis) using a sensor bracket: The X-and Y-axis sensors are oriented along the geomagnetic north-south and east-west direction, respectively. The SCM system block diagram is shown in Fig. 2. Magnetic sensing signals detected by two axis sensors are amplified by the pre-amplifiers and transmitted to the main electronics through a 200-m cable. The signals from each sensor are fed to the single main cable via a junction box located between the sensors and main electronics. The main analog board has a secondary amplifier and ...
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... A search coil-based magnetometer was designed for extracting a time-varying magnetic field in the ultra-low frequency (ULF) range (1 mHz to 5 Hz) with a sensitivity of 365 µV/nT for space research applications. The operation of the device was based on LabVIEW with a dedicated data acquisition system making the whole setup complex and bulky [20]. The reported devices in the literature are incapable of providing a wide AC magnetic field range over a larger frequency band. ...
... With decent operating range and accuracy, the developed device was low-cost and small-sized among all the available devices. Also, as per the available literature no such economical and miniaturized device exists which can cover a wide frequency range for measuring magnetic field with an accuracy of less than 4% [2], [18]- [20]. ...
This paper presents the design of a low-cost and hand-held device for measuring low magnetic fields over a wide frequency band i.e., 50 Hz to 30 kHz. The device primarily consists of a self-designed detector coil and field display unit comprising dedicated signal conditioning circuitry, analog-to-digital converter (ADC), microcontroller, and organic light emitting diode (OLED) screen. The coil senses the variation in the magnetic field in terms of voltage signal which is displayed on the screen after suitable hardware and software processing. The validation of the developed device was performed with a Helmholtz coil. In measuring magnetic field values from 10mG to 2000 mG, the device depicted exceptional accuracy, sensitivity, linearity, and frequency response parameters. In comparison to similar available magnetometers, the developed device showed a remarkable closeness in measurement. The developed device can become an affordable and reliable means for monitoring magnetic fields that have significant applications in electromagnetic interference/electromagnetic compatibility (EMI/EMC) measurements, healthcare, etc.
... The X-axis of the magnetometer points to the north magnetic pole and the Y-axis (orthogonal to X) is eastward. The noise level of the magnetometer is 0.07 pT/Hz2 at 1 Hz with a sampling rate of 10 Hz (Shin et al., 2016). The SNK magnetometer was operational from October 2015 to September 2018. ...
In the present study, we explore the observational characteristics of Electromagnetic Ion Cyclotron (EMIC) wave propagation from the source region to the ground. We use magnetometers aboard Geostationary Operational Environment Satellite (GOES) 13, the geosynchronous orbit satellite at 75°W, and at Sanikiluaq ground station (SNK, 79.14°W and 56.32°N in geographic coordinates, and L ∼ 6.0 in a dipole magnetic field) which is located in northern Canada. Using these magnetically conjugate observatories, simultaneous EMIC wave observations are carried out. We found a total of 295 coincident and 248 non‐coincident EMIC wave events between GOES 13 and the SNK station. Our statistical analysis reveals that the coincident events are predominantly observed on the dayside. The wave normal angles are slightly higher for the non‐coincident events than for coincident events. However, the coincidence of the waves is mostly governed by the intensity and duration of the wave. This is confirmed by the geomagnetic environment which shows higher auroral electrojet (AE) and Kp indices for the coincident events. We also found that some events show high‐frequency (f > 0.4 Hz) wave filtering. The statistics of the high‐frequency filtered and non‐filtered wave events show that there are clear magnetic local time (MLT) and F10.7 index differences between the two groups, as well as in ionospheric electron density measurements. In addition, we also found differences in the wave properties which possibly indicate that the propagation in the magnetosphere also plays an important role in the wave filtering.
... The result of Figure 9 shows the unexpected Z-component peak at approximately 3.8 Hz. We further examined the peak value by performing a test keeping a search-coil magnetometer used for ground observation (Shin et al. 2016) inside the shielding chamber. The test showed that the noise was over 20 dB at approximately 3.8 Hz. ...
Kplo-MAGnetometer (KMAG) is one of the scientific instruments of Korea Pathfinder Lunar Orbiter (KPLO) set to be launched in 2022. Its objectives are magnetic field investigation and technical demonstration near the surface of the Moon. Specifically, it will investigate the lithospheric magnetism of the Moon and measure the electromagnetic wave properties near the lunar surface. It consists of three fluxgate magnetometers on a 1.2 m long boom, which is relatively shorter than the boom used in other missions. The three magnetometers are included for scientific measurements, redundancy checks, and multi-sensor technical investigation. The magnetometers and an inner Anisotropic Magneto-Resistive sensor perform simultaneous sampling to correct for the magnetic field interference caused by the spacecraft. The fully integrated flight model assembly showed that the magnetometer noise level was less than 30 pT Hz−1/2 at 1 Hz and stability was within ±0.2 nT at the 10 Hz sampling rate. This paper describes the configuration and performance of the KMAG using the multi-sensing method. KPLO, THEMIS-ARTEMIS spacecraft, and Commercial Lunar Payload Service modules will be in their operational phase simultaneously. Therefore, the KMAG will be able to contribute to multi-site in-situ measurements of the lunar magnetic field. We expect that the KMAG will provide an up-to-date lunar observation data set and an opportunity to perform the multi-sensor observation. © 2021. The Astronomical Society of the Pacific. All rights reserved.
... The SCM measures the magnetic field variations (AC field), while the vector magnetometer measures the magnitude of the magnetic The SCM was developed by the Kyung Hee University in collaboration with the University of New Hampshire and was installed during the 2016-2017 austral summer season. The SCM consists of two magnetic sensors ( Fig. 5(a)) assembled orthogonally to sample the AC magnetic field (dB/dt) in the horizontal components, and magnetically northward (X) and magnetically eastward (Y) at a rate of 0.1 s (Shin et al. 2016). The SCM was placed on the east side of the SWO at a distance of ~250 m to avoid artificial noise. ...
Jang Bogo Station (JBS), the second Korean Antarctic research station, was established in Terra Nova Bay, Antarctica (74.62°S 164.22°E) in February 2014 in order to expand the Korea Polar Research Institute (KOPRI) research capabilities. One of the main research areas at JBS is space environmental research. The goal of the research is to better understand the general characteristics of the polar region ionosphere and thermosphere and their responses to solar wind and the magnetosphere. Ground-based observations at JBS for upper atmospheric wind and temperature measurements using the Fabry-Perot Interferometer (FPI) began in March 2014. Ionospheric radar (VIPIR) measurements have been collected since 2015 to monitor the state of the polar ionosphere for electron density height profiles, horizontal density gradients, and ion drifts. To investigate the magnetosphere and geomagnetic field variations, a search-coil magnetometer and vector magnetometer were installed in 2017 and 2018, respectively. Since JBS is positioned in an ideal location for auroral observations, we installed an auroral all-sky imager with a color sensor in January 2018 to study substorms as well as auroras. In addition to these observations, we are also operating a proton auroral imager, airglow imager, global positioning system total electron content (GPS TEC)/scintillation monitor, and neutron monitor in collaboration with other institutes. In this article, we briefly introduce the observational activities performed at JBS and the preliminary results of these observations.
