• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.03a
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• pp.278-281
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• 2004

To realize magnetic sails, momentum of the solar wind should be efficiently transferred to a spacecraft via magnetic field, which is produced around a spacecraft. In this paper, two important physical processes are addressed: 1) diffusive processes caused by plasma turbulence at the magnetospheric boundary around the spacecraft; and 2) field aligned current loops that will electrically connect the magnetospheric boundary and the spacecraft. The idea of the magnetic sails will be demonstrated by an experimental simulator, in which a fast plasma beam will penetrate into a dipole magnetic field. For that purpose, the two important physical processes should be scaled down to a small laboratory experiment in a space chamber. From the scaling considerations, the interaction can be scaled down if high-speed and high-density $(10^{19}m^{-3})$ plasma jet is used with 1-T-class magnetic field.

• 한국지구물리탐사학회:학술대회논문집
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• 2006.06a
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• pp.141-151
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• 2006

A blank test was done to calculatee the car itself's magnetic effect as noise and to eliminate it from the data set of total magnetic intensity(=magnetic flux density) exploration in a car-borne magnetic exploration system. To calculate the induced magnetic intensity(= magnetization) and the remanent magnetic intensity(= magnetization) of the car itself, we have installed the magnetometer on a fixed point and measured the magnetic intensity letting the car move around the magnetometer, and we have changed the data set into an analogous data set as if acquired in the condition that we have parked the car on the same fixed point and measured the magnetic intensity moving the magnetometer around the magnetometer. Through an inversion with the later data set as input, we have calculated the magnetic center and the magnetic moments of the induced magnetic intensity(= magnetization) and the remanent magnetic intensity(= magnetization) of the car itself with the two centers coincided because of some barriers of the inversion algorithm that we have used in this study. On the other hand, we have extracted the magnetic anomaly by reducing i. e. vectorially eliminating the induced magnetic intensity(= magnetization) and the remanent magnetic intensity(= magnetization) of the car itself calculated forwardly, from the magnetic exploration data set acquired by the car-borne magnetic exploration system.

• Geophysics and Geophysical Exploration
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• v.23 no.3
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• pp.178-191
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• 2020

Unmanned aerial vehicle (UAV) technologies have grown rapidly over the past decade. Simultaneously, there is an increasing need for efficient high-resolution exploration techniques in complex environments. As a result, exploration technology using UAVs is gaining attention as an efficient method to complement and replace existing exploration technologies. In particular, magnetic exploration technology with UAVs is rapidly gaining ground in the field of exploration and is expected to be actively used in this field in the future. To properly use such technology in domestic exploration, it is necessary to review the latest research trends. Accordingly, this paper introduces the current state of UAV-based magnetic exploration technology studies and, based on this, discusses future research directions.

• Geophysics and Geophysical Exploration
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• v.11 no.4
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• pp.343-349
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• 2008

We have constructed a car-borne magnetic exploration system, in which a car drags a non-magnetic cart on which a magnetometer is installed. In the total magnetic field measured as a vectorial sum in this system, are included the magnetic field generated by the car itself. This magnetic field, doing the role of a magnetic noise, should be eliminated. For this purpose, we have set up a measurement condition to get the same effect as if we have put the car in one point and thereafter measured the magnetic field around it. In this case, if there is any magnetically anomalous body in the area, we can consider all the remaining magnetic field to have been generated by the car itself, once the geomagnetic field eliminated. We tried to invert the magnetic field considered to have been generated by the car and succeeded to derive the magnetic moment and the direction of the induced and remanent magnetic field of the car respectively. Once the magnetic moment and the direction of the induced and remanent magnetic field have been calculated, the magnetic field generated by them in specific points can be directly and analytically calculated. This result can be used in the future to eliminate the magnetic field generated by the car itself doing the role of a magnetic noise during the procedure of reduction of the measured magnetic exploration data by the car-borne magnetic exploration system.

• 한국지구물리탐사학회:학술대회논문집
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• 2008.10a
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• pp.13-20
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• 2008

Magnetic method is rapid, cheap and simple geophysical exploration technique, and has wide range of applications such as resources prospecting, geological structure investigation and even geotechnical and environmental problems. Documents during Japanese occupation says that magnetic method was used for exploring metallic ore deposits and hot spring, and that a geomagnetic observatory was operated. From mid 1950's, magnetic explorations for natural resources such as metallic ore, uranium, coal, and groundwater were intensively executed for industrialization. Magnetic survey techniques were rapidly advanced during 1970's and 1980's with improvements of instruments, growth of geophysical manpower, and availability of computers. Decline of mining industry since mid 1980's moved the exploration objects from traditional resources to new ones such as groundwater and geothermal resources. Recently appeared applications such as natural hazard assessment, and engineering and environmental studies increased the magnetic method's utility in the realm of exploration.

• Geophysics and Geophysical Exploration
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• v.23 no.3
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• pp.208-214
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• 2020

In this study, we have developed a drone magnetic exploration system (proto-type) using a fluxgate magnetic sensor. Hardware of the system consists of a fluxgate magnetometer, an inertial measurement unit (IMU), a GPS, and a communication module. And we have developed monitoring software, which enables it to transmit the measured data to the ground control system (GCS) in real time. The measured magnetic data are finally saved as 1 Hz data after passing through a notch filter and a band-pass filter. For verification of this system, a preliminary test was conducted to check the magnetic responses of a magnetic object first, then the field test was carried out in two iron mines. We tested the developed system on the field test in Pocheon, Gyeonggi and Jeongseon, Gangwon. The magnetic data from the developed drone system was very similar to those from unmanned airship system developed by Korea Institute of Geoscience and Mineral Resources (KIGAM). As a result, preliminary experiment and field test have demonstrated that this system is applicable for outdoor aeromagnetic exploration. It requires more studies to improve filter function and instrument performance to minimize noise in the future.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.03a
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• pp.553-556
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• 2008

A Magneto Plasma Sail(MPS) produces propulsive force by the interaction between the solar wind and an artificial magnetic field inflated by injecting plasma. Using a 2D hybrid PIC code, we evaluate the inflation of magnetic field when Argon(Ar) plasma with different ${\beta}_{in}$ including the value less than one is injected into the dipolar magnetic field generated by a superconducting coil. It is found that the magnetic field can be inflated by injecting plasma within an angle of $30^{\circ}$ in the polar direction and the magnetic field decays in the polar direction according to $B{\propto}r^{-2.4}$ after the plasma(${\beta}_{in}$=0.1) is injected.

• Geophysics and Geophysical Exploration
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• v.17 no.3
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• pp.147-154
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• 2014

For analyzing the distribution of chromite, magnetic survey was carried out on the chromium mineralized belt in Bophi Vum area, northwestern Myanmar. As a result, the magnetic susceptibility of chromite is lower than those of dunite and harzburgite, which are background rocks of chromite. Also, the locations of low magnetic anomaly zone and low magnetic susceptibility models of 3D magnetic inversion result are spatially well matched with those of chromite occurrences confirmed by the surface geological survey and trench survey. Some of low magnetic effects are expanded to the periphery area of chromite occurrences. Considering the magnetic susceptibility characteristics of various rocks in this area, the expanded low magnetic anomaly zones are estimated as the high potential areas bearing chromite. For confirming the potential area of chromite pointed by coarse magnetic survey, the additional detail exploration need to be carried out in future.

• Geophysics and Geophysical Exploration
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• v.22 no.1
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• pp.29-36
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• 2019

Regional airborne magnetic survey is very cost-effective mapping tool. Magnetic anomaly maps have abundant information, which are an important tool for understanding the geological evolution and mineral exploration. For this reason, the governments of many countries have made significant investment in the acquisition of airborne geophysical data over many decades. KIGAM (Korea Institute of Geoscience and Mineral Resources) began nationwide airborne magnetic mapping programme in 1982, and completed in 2017. The obtained magnetic data was reprocessed and magnetic database was built in 2018. In addition, the magnetic anomaly map of Korea with a scale of 1:1,000,000 was published. In this paper, we introduced a new magnetic anomaly map of Korea through describing the changing survey parameters during data acquisitions and history of data processing.

• Economic and Environmental Geology
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• v.39 no.4 s.179
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• pp.403-416
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• 2006

Magnetic method is rapid, cheap and simple geophysical exploration technique, and has wide range of applications such as resources prospecting, geological structure investigation and even geotechnical and environmental problems. Especially, aeromagnetics gives fundamental and useful geoscientific data fnr not only assessment of potential resources, but also national land planning. Magnetic method, perhaps the oldest geophysical technique, was relatively early introduced into Korea. Documents during Japanese occupation says that magnetic method was used for exploring metallic ore deposits and hot spring, and that a geomagnetic observatory was operated. From mid 1950's, after Korean War, magnetic explorations for natural resources such as metallic ore, uranium, coal, and groundwater were intensively executed for industrialization. Apache aeromagnetic survey project during $1958{\sim}1959$ and its ground follow-up surveys are typical and important cases in those days. Magnetic survey techniques were rapidly advanced during 1970's and 1980's with improvements of instruments, growth of geophysical manpower, and availability of computers. The national aeromagnetic mapping project by KIGAM in 1981 showed the improved technical capability of those days. Decline of mining industry since mid 1980's moved the exploration objects from traditional resources to new ones such as groundwater and geothermal resources, and applications to investigation of geological structure were revived. Recently appeared applications such as natural hazard assessment, and engineering and environmental studies increased the magnetic method's utility in the realm of exploration.