VLF 1) emissions from the ionosphere. | ||
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The magnetic activities
that follows an Aurora, may also generate audiable electrical signals. With a simple electronic equipment you can listen
to them. These sounds lag the main phase of the Aurora by typically 6 - 12 hours, with a
significant occurance at dawn. The spectrograms below show the complex and endless variation, with or without magnetic unrest. |
A whistler's signature The aftermath of Aurorae
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A multireflexion whistler. Decreasing amplitude and increasing dispersion is in effect. Note the timescale. Some 30 seconds are seen. |
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Dawn chorus. Also two hissbands are evident. The night was magnetically active. |
A cluster of risers. The local magntic condition was quiet. |
Intense broandband hiss. The aftermath of a major magnetic storm during the night. |
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Some pure tones. Some magnetic activity. |
Hooks are abound. Magnetic quiet condition. | |
Whistler mania. The now obsolete Omega is visible. No magnetic activity. |
1) Very Low Frequency electromagnetic energy