Ion cyclotron bands in VLF saucers
In the wideband VLF data obtained by the polar orbiting DE-1 satellite over the polar night ion trough region of the upper ionosphere, conspicuous frequency-band structures are found to occur both in absorption and emission, particularly associating with VLF saucers. The attenuation bands indicate t...
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ftnasantrs:oai:casi.ntrs.nasa.gov:19900048325 2023-05-15T18:02:16+02:00 Ion cyclotron bands in VLF saucers Maeda, Kaichi Fung, Shing F. Calvert, Wynne Unclassified, Unlimited, Publicly available Apr 1, 1990 http://ntrs.nasa.gov/search.jsp?R=19900048325 unknown http://ntrs.nasa.gov/search.jsp?R=19900048325 Accession ID: 90A35380 Copyright Other Sources 46 Planetary and Space Science; 38; 507-509 1990 ftnasantrs 2012-02-15T18:30:25Z In the wideband VLF data obtained by the polar orbiting DE-1 satellite over the polar night ion trough region of the upper ionosphere, conspicuous frequency-band structures are found to occur both in absorption and emission, particularly associating with VLF saucers. The attenuation bands indicate that the ions of atomic hydrogen from the polar ionosphere are accelerated by the ac electric fields of VLF waves oscillating normal to the static magnetic field, analogous to a cyclotron accelerator. The observed frequencies of the cyclotron harmonics suggest that the acceleration is taking place in the layer below the satellite at a geocentric distance of less than about 1.5 earth radii. This example indicates the existence of upward propagating hiss at those altitudes inside the auroral zone. On the other hand, the frequency shifts of the emission bands are attributed to a combination of two different types of Doppler shift, one due to the orbital motion of the satellite and the other due to the upward motion of the medium at the emission source. This indicates the existence of an upward plasma flow at the source, with a velocity of the order of 20 km/s inside the saucer. The amount of this frequency shift decreases with increasing harmonic order, indicating a higher phase velocity for the electrostatic waves of higher harmonic order. Other/Unknown Material polar night NASA Technical Reports Server (NTRS) |
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46 Maeda, Kaichi Fung, Shing F. Calvert, Wynne Ion cyclotron bands in VLF saucers |
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46 |
description |
In the wideband VLF data obtained by the polar orbiting DE-1 satellite over the polar night ion trough region of the upper ionosphere, conspicuous frequency-band structures are found to occur both in absorption and emission, particularly associating with VLF saucers. The attenuation bands indicate that the ions of atomic hydrogen from the polar ionosphere are accelerated by the ac electric fields of VLF waves oscillating normal to the static magnetic field, analogous to a cyclotron accelerator. The observed frequencies of the cyclotron harmonics suggest that the acceleration is taking place in the layer below the satellite at a geocentric distance of less than about 1.5 earth radii. This example indicates the existence of upward propagating hiss at those altitudes inside the auroral zone. On the other hand, the frequency shifts of the emission bands are attributed to a combination of two different types of Doppler shift, one due to the orbital motion of the satellite and the other due to the upward motion of the medium at the emission source. This indicates the existence of an upward plasma flow at the source, with a velocity of the order of 20 km/s inside the saucer. The amount of this frequency shift decreases with increasing harmonic order, indicating a higher phase velocity for the electrostatic waves of higher harmonic order. |
format |
Other/Unknown Material |
author |
Maeda, Kaichi Fung, Shing F. Calvert, Wynne |
author_facet |
Maeda, Kaichi Fung, Shing F. Calvert, Wynne |
author_sort |
Maeda, Kaichi |
title |
Ion cyclotron bands in VLF saucers |
title_short |
Ion cyclotron bands in VLF saucers |
title_full |
Ion cyclotron bands in VLF saucers |
title_fullStr |
Ion cyclotron bands in VLF saucers |
title_full_unstemmed |
Ion cyclotron bands in VLF saucers |
title_sort |
ion cyclotron bands in vlf saucers |
publishDate |
1990 |
url |
http://ntrs.nasa.gov/search.jsp?R=19900048325 |
op_coverage |
Unclassified, Unlimited, Publicly available |
genre |
polar night |
genre_facet |
polar night |
op_source |
Other Sources |
op_relation |
http://ntrs.nasa.gov/search.jsp?R=19900048325 Accession ID: 90A35380 |
op_rights |
Copyright |
_version_ |
1766172069347721216 |