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Magnetometry Geomagnetometry is the study of the Earth's magnetic field and how it interacts with the local surroundings and includes the study of worldwide geomagnetic disturbances (geomagnetic storms) caused by the solar wind and disturbances caused by natural events such as earthquakes and possibly volcanic activity nearby. A geomagnetometer, or just magnetometer, is an instrument used to measure the magnetic field. Click here for real time magnetometer data from our Anchorage observatory. Click here for an article that includes a tutorial on geomagnetism as well as a description of the Simple Aurora Monitor used in our observatory. We are using a three phase approach in our study of geomagnetism, as described below. We presently are in Phase II.
Phase I - Basic experimental phase to build a relatively simple magnetometer system based on the Speake & Co Llanfapley FGM-3 or FGM-3h magnetic sensor and their SLC-006B application specific integrated circuit (ASIC). Click here for detailed information on the FGM-3 and FGM-3h sensors used in our applications. The Phase I experimental setup is used to determine the local magnetic field environment through calibration of the sensor using a known field. The known magnetic field is generated by a long coil of known dimensions and wire turns carrying a known current. The sensor is inserted in the coil and measurements made for various orientations. These are then compared to measurements made with the sensor in its field environment. Sensor characterization studies are not yet completed.
Phase II - Advanced experimental and monitoring phase to build a more advanced geomagnetometer system also based on the FGM-3 or FGM-3h. The Phase II experimental setup is used to study the feasibility of correlating local magnetic field measurements with very low frequency (VLF) electric field measurements and solar events. We commissioned Phase II on May 27, 2009 based on the Simple Aurora Monitor (SAM). Click here for real time geomagnetometer data. The Phase II installation was completed May 26, 2009 with the Simple Aurora Monitor (SAM) signal processor and FGM-3 sensor. The sensor is buried approximately 50 cm below ground level to prevent diurnal temperature variations from affecting the sensor. The sensor cable is 2-pair, 22 AWG shielded buried service cable approximately 40 m long.
Phase III - Monitoring phase to build a magnetometer system that will use a customized approach incorporating the results from Phase I and Phase II. |
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