Sudden Ionospheric Disturbances Supplement
From September 2001 Solar Bulletin Casper H. Hossfield, SID Sup. Editor
PO Box 23
New Milford, NY 10959, USA | SUDDEN IONOSPHERIC DISTURBANCES
RECORDED DURING September, 2001 | capaavso@aol.com
Fax 973 853 2588 |
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Lars Pettersson, in Odensbacken, Sweden made the above magnetogram using a Flodqvist magnetometer. He emailed it to me as a DAT file and I used Piclogger32D plotting software to plot it as it would appear if recorded on a Rustrak strip chart recorder running at the standard chart speed of ¼ inch/hr. Piclogger32D can plot any DAT file as a Rustrak recording including SID recordings at 1-inch/hour. This software is free from the AAVSO. If you would like a copy send me an email at my address above. Complete instructions how to build the Flodqvist magnetometer can be found in the October, 1993 issue of Sky & Telescope magazine. It is a very simple magnetometer made from an ordinary magnetic compass. A solenoid balances the compass in an East-West direction with the needle acting as a shadow vane over a photo transistor. The balancing current in the solenoid is controlled by the phototransistor. If the Earth's magneic field changes in response to a magnetic storm it disturbs the balance and the phototransistor automatically restores the balance. The change in current to restore balance is amplified and recorded to make the chart above. You can also get instructions how to build the magnetometer by sending an email to << gote.flodqvist@ebox.tninet.se >> For additional information see also Gote's website at http://user.tninet.se/%7Esdt522w/. Some of you may remember Gote as an AAVSO SID observer who made excellent multiplexed charts of three SES recordings using very sensitive VLF receivers of his own design. Some of you may also have met him at the AAVSO Eclipse Site in Petersburg, Virginia for an annular eclipse. It was raining the morning of the eclipse so we drove down to a clear site in Greensboro, North Carolina and barely made it in time for Gote to set up his eclipse camera and take some nice photographs. We had to hurry in order to make it to Greensboro in time and I got a ticket for speeding 85mph but that is the price you pay for being an eclipse chaser.
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Roberto Battaiola, A-96, in Italy made the interesting SID recording above. It shows a big SES lasting 5 hours! It took ½ hour to rise to maximum and stayed at maximum for almost 2 hours. I cannot remember seeing an SES last this long before. Roberto used Piclogger32D to plot this recording at ¼ inch/hour. Another very long lasting SES is shown below on the next page.
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Jim Mandaville, A-90, recorded another long lasting SES on 25 August, the next day after Roberto recorded his long lasting one. Jim's recording is shown above. His lasted about 4 ½ hours and shows four other SESs, one of them superimposed on the long lasting SES. Jim lives near Tucson, Arizona and records NPM in Hawaii transmitting on 21.4 kHz
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Walter Moos, A-84, made the inverted SES recording above of VLF station FTA. He lives near Bern, Switzerland about 500 km from FTA in St. Assis, France. It is not unusual to record inverted SESs from a station at this distance. The SES takes about 20 minutes to reach maximum intensity at 1024 UT and about an hour to decay to normal at 1254 UT
