Accession Number : AD0488714

Title :   A SATELLITE STUDY OF VLF HISS,

Corporate Author : IOWA UNIV IOWA CITY DEPT OF PHYSICS AND ASTRONOMY

Personal Author(s) : Gurnett, Donald A.

Report Date : JUN 1966

Pagination or Media Count : 66

Abstract : Broad-band VLF radio noises from about 4 kc/s to above 10 kc/s are frequently observed near the auroral zone with the Injun 3 satellite. These broad-band VLF radio noises are called VLF hiss. In this study we select VLF hiss events for analysis by requiring that the radio noise intensity from 5.5 to 8.8 kc/s exceed 3 x 10 to the -10th power gamma 2/cps (about 5 times the receiver noise level). The frequency spectra of the VLF hiss observed by Injun 3 is typically a flat noise spectrum with a distinct lower frequency cutoff. The lower frequency cutoff is often found to have a nearly symmetric latitude variation centered on a region of intense electron precipitation. The range of invariant latitudes (INV) for which VLF hiss typically occurs is about 10 wide and centered on 77 INV at 12.0 hours magnetic local time (MLT), decreasing to 72 INV at 23.0 hours MLT. On the high latitude side of the 40 keV trapping boundary, where VLF hiss usually occurs, intense fluxes of soft electrons are often accompanied by FLF hiss. It is found that the correlation between VLF hiss and intense fluxes (j > 2.5 x 10 to the 7th power (sq. cm ster sec)-1 of electrons (E > 10 keV) is dependent on the exponential folding energy E. The correlation is very good for E from 3 to 4 keV but poor for larger E values. (Author)

Descriptors :   *SCIENTIFIC SATELLITES), (*NOISE(RADIO), VERY LOW FREQUENCY, MAGNETIC FIELDS, SPECTRUM ANALYZERS, RADIATION MEASURING INSTRUMENTS, ELECTRON MULTIPLIERS, DENSITY, AURORAE, EMISSIVITY, INTENSITY, STATISTICAL ANALYSIS.

Subject Categories : Radio Communications

Distribution Statement : APPROVED FOR PUBLIC RELEASE