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Spaceborne observations of radio noise from 0.7 to 7.0 MHz and their dependence on the terrestrial environment

Published online by Cambridge University Press:  14 August 2015

G. R. Huguenin  and
M. D. Papagiannis
G. R. Huguenin
Affiliation:
Harvard College Observatory Cambridge, Massachusetts, U.S.A.
M. D. Papagiannis
Affiliation:
Harvard College Observatory Cambridge, Massachusetts, U.S.A.

Abstract

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Observations of long-wavelength (λ > 30 m) radio radiation in space are reported and analyzed in the framework of the terrestrial environnement.

Measurements at low altitudes (~ 300 km) at the frequencies of 4.0 and 7.0 MHz have revealed the existence of very high radio noise levels during the night and on certain occasions during the day. These strong signals were at least 50 db higher than the expected cosmic background and are attributed to man-made and atmospheric radio noise.

Measurements at high altitudes (3000–11000 km) at the frequencies of 2.2 and 0.7 MHz have produced a flux value at 2.2 MHz in agreement with the expected cosmic radio background, but the flux value obtained at 0.7 MHz is approximately 15 db higher than the anticipated flux from cosmic sources. Harmonic gyroradiation from the artificial and the outer Van Allen belts might be the cause of the high radio flux observed at 0.7 MHz.

On rend compte d'observations du rayonnement hertzien dans l'espace sur des longueurs d'onde supérieures à 30 m. On analyse ces résultats en tenant compte de l'environnement terrestre.

Aux attitudes voisines de 300 km et sur les fréquences de 4,0 et 7,0 MHz, on a constaté l'existence de niveaux de bruit trés élevés pendant la nuit et dans certains cas pendant le jour. Ces signaux sont au moins 50 db au-dessus du bruit cosmique auquel on peut s'attendre et ils sont attribués aux atmosphériques et aux parasites industriels.

Les mesures à des attitudes comprises entre 3000 et 11000 km fournissent des valeurs du flux sur 2,2 MHz voisins des valeurs prévues pour le bruit cosmique alors que sur 0,7 MHz le niveau requ est 15 db au-dessus des valeurs prévues. On suggère que le rayonnement cyclotron des ceintures de Van Allen et de la ceinture artificielle pourrait expliquer les observations sur 0.7 MHz.

Резюме

Резюме

приведен отчет о наблюдениях герцевого излучения в пространстве на длине волн превосходящих 30 м. Эти результаты проанализированы учитывая окружение Земли.

На высотах около 300 км. и в частотах 4.0 и 7.0 мгц было констатировано существование очень высоких шумовых уровней ночью, а в некоторых случаях-днем. Эти сигналы превышают по крайней мере на 50 бол. гр. космический шум, который можно ожидать, и их приписывают атмосферикам и индустриальным паразитам.

Измерения на высотах заключенных между 3.000 и 11.000 км. дают значения потока в 2,2 мгц близкие к значениям предвиденным для космического шума. Тогда как в 0,7 мгц полученный уровень превышает на 15 бол. гр. предвиденные значения. Выдвинута мысль, что циклотронное излучение поясов Ван Аллена и искусственного пояса смогли-бы объяснить наблюдения в 0,7 мгц.

Type
Session VII. Radio Frequency Radiation
Information
Symposium - International Astronomical Union , Volume 23: Astronomical Observations from Space Vehicles , 1965 , pp. 309 - 317
Copyright
Copyright © CNRS 1965 

References

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