Accession Number : AD0785011

Title :   Solar-Geophysical Effects on Northern and Mid-Latitude ELF Propagation.

Descriptive Note : Interim rept.,

Corporate Author : NAVAL RESEARCH LAB WASHINGTON D C

Personal Author(s) : Davis,John R. ; Meyers,William D.

Report Date : 12 JUL 1974

Pagination or Media Count : 26

Abstract : The ionospheric phenomena that have the greatest effect on ELF propagation occur at middle to northern latitudes under conditions of path darkness. Polar cap events cause increased ion densities in the polar lower D region; these events can lead to greatly increased absorption of northern latitude paths. Under nighttime conditions, precipitated electrons can affect transmitting and receiving stations in the auroral zone by enhancing the conductivity of the lower E region. Precipitation of charged particles trapped in the outer radiation belt can affect stations and paths at even lower latitudes. Examples of ELF propagation data under disturbed conditions are rare, but the few that have been recorded in recent years show significant correlation with solar proton flux emissions, galactic cosmic ray fluctuations, auroral and polar cap absorption events, and geomagnetic storms. These correlations permit a preliminary, qualitative confirmation of the effects that solar charged particle emissions were expected to have on ELF propagation. (Author)

Descriptors :   *Radio transmission, Extremely low frequency, Aurorae, Ionosphere, Atmospheric electricity, Ionospheric disturbances, Magnetic storms, Field intensity

Subject Categories : Atmospheric Physics
      Radiofrequency Wave Propagation
      Radio Communications

Distribution Statement : APPROVED FOR PUBLIC RELEASE