Accession Number:

AD0676887

Title:

VLF EMISSIONS DURING MAGNETIC STORMS AND THEIR ASSOCIATION WITH 40 keV ELECTRONS,

Descriptive Note:

Corporate Author:

IOWA UNIV IOWA CITY DEPT OF PHYSICS AND ASTRONOMY

Personal Author(s):

Report Date:

1968-07-01

Pagination or Media Count:

45.0

Abstract:

Spectrograms of very low frequency radio noise recorded by University of Iowa satellite Injun 3 at invariant latitudes greater than 50N are used to determine the behavior of VLF emissions during magnetic storms. Variations in the wideband intensity of VLF emissions from L 3 to L 8 are studied for the period from 28 April to 28 August 1963 by means of the automatic gain control levels of the satellite VLF receiver. During a sudden-commencement magnetic storm the VLF emission called polar chorus characteristically appears at the onset of the storm, may increase in upper frequency extent to approximately 5 kHz, may change from spike to burst structure normal chorus, and occurs over the greatest area on the fourth day of the storm, subsequently fades into low frequency, spike-structure polar chorus again and eventually disappears into the ELF hiss band generally present. Chorus occurrence shows symmetry about the 900 - 2100 magnetic local time meridian with a large maximum in magnetic morning and a smaller maximum in magnetic evening. Daily regions of occurrence are shown for the duration of a prototypical storm. Author

Subject Categories:

  • Geomagnetism

Distribution Statement:

APPROVED FOR PUBLIC RELEASE