17:15 〜 19:15
[PEM10-P20] デジタル画像記録方式ソーダボトル磁力計を用いた観測及びデータ処理教育
キーワード：地球科学実験教育、地磁気観測、手作り磁力計
The soda bottle magnetometer, which is a handmade torsion-type magnetic variometer, has been used for space weather education in middle-to-high latitude regions. However, this teaching material is rarely used in magnetically low latitude regions such as Japan because manual reading of the light spot reflected from the mirror attached to the sensor magnet cannot resolve small magnetic field fluctuations. In order to use the soda bottle magnetometer for a class at Kyoto University, I combined it with a data recording system that uses a webcam to take regular images of the position of the light spot, called the "Digital Image-Recording Soda Bottle Magnetometer". The data was recorded by taking 96 images at 4 images/s for 24 seconds every 5 minutes. The center positions of the light spot were accurately determined from the digital images using Python programs. The resolution of the magnetic declination is less than ~0.08 arcmin (or ~0.7 nT of east-west magnetic fields at Kyoto), which is about ten times better than the manual reading. The new type of soda bottle magnetometer successfully detected Sq variations and substorm magnetic bays at Kyoto (GMLat~25 degree) with amplitude < 5 nT as well as strong magnetic fluctuations of geomagnetic storms. Since images of light spots are acquired as digital data, students can analyze the data themselves on their computers. The cost of the observing system is low (less than 10,000 yen, excluding the PC). The digital image recording soda bottle magnetometer has potential for use in space weather education not only in universities, but also in high schools and citizen science.