VISNJAN, August, 2000

The Group constructed magnetometer and measured changes in Earth's magnetic field for less then two days which is a too short period of time to make good calibrational measurements for comparisons with other magnetometers. What we learned making this magnetometer is the principle for detecting and measuring the magnetic field of Earth. We also noticed that the magnetometer described in Scientific American can be constructeded to measure even smaller differences just by adding Helmholtz arrangement around box with magnets. We tried to do that and while it was working magnetometer was more sensitive. Unfortunately, we had a large number of problems with magnet stability and keeping laser beam between the photocells. Some other improvements are also needed. For example, one could put everything inside large black plastic box to minimize the effect of daylight. We considered a proposal to combined Helmholtz coils with photocells and electronic feedback to keep the laser beam fixed as the earth's field changes. Measuring the current needed to null the signal in this way shows the size of the magnetic fluctuations.  

Some curves of calibration and other ..

Some related sites:
http://www.sec.noaa.gov/Data/geomag.html#measurements
http://www.sciam.com/1999/0199issue/0199amsci.html
http://www.spaceweather.com/
http://geomag.usgs.gov/frames/plots.htm
http://www.sec.noaa.gov/
 

VSA 2000 REPORT

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