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Quantitative relationship between VLF phase deviations and 1-8 A solar X-ray fluxes during solar flares

Abstract

An attempt is made to investigate the quantitative relationship between VLF phase deviations in SPA (sudden phase anomalies) events and associated solar X-ray fluxes in the 1 to 8 A band during solar flares. The phase deviations (..delta..phi) of the 18.6 kHz VLF wave transmitted from NLK, USA are used in this analysis which were recorded at Nishinomiya, Japan during the period June 1974 to May 1975. The solar X-ray fluxes (F/sub 0/) in the 1 to 8 A band are estimated from fsub(min) variations using the empirical expression given by Sato (J.Geomag.Geoelectr.;27: 95(1975)), because no observed data were available on the 1 to 8 a X-ray fluxes during the period of the VLF observation. The result shows that the normalized phase variation, ..delta..phi/coschisub(min), where chisub(min) represents the minimum solar zenith angle on the VLF propagation path, increases with increasing logF/sub 0/. A theoretical explanation for this is presented assuming that enhanced ionizations produced in the lower ionosphere by a monochromatic solar X-ray emission are responsible for the VLF phase deviations. Also it is found that a threshold X-ray flux to produce a detectable SPA effect is approximately 1.5 x 10/sup -3/ cm/sup -2/ sec/sup -1/ in the 1 to  More>>
Authors:
Muraoka, Y; Murata, H; Sato, T [1] 
  1. Hyogo Coll. Of Medicine (Japan). Dept. of Physics
Publication Date:
Jul 01, 1977
Product Type:
Journal Article
Reference Number:
AIX-09-357543; EDB-78-047382
Resource Relation:
Journal Name: J. Atmos. Terr. Phys.; (United Kingdom); Journal Volume: 39:7
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; SUDDEN IONOSPHERIC DISTURBANCE; SOLAR X-RAY BURSTS; CORRELATIONS; D REGION; KHZ RANGE 01-100; RADIATION FLUX; SOLAR FLARES; SOLAR RADIATION; WAVE PROPAGATION; X RADIATION; DISTURBANCES; EARTH ATMOSPHERE; ELECTROMAGNETIC RADIATION; FREQUENCY RANGE; IONIZING RADIATIONS; IONOSPHERE; IONOSPHERIC STORMS; KHZ RANGE; RADIATIONS; SOLAR ACTIVITY; 640201* - Atmospheric Physics- Auroral, Ionospheric, & Magetospheric Phenomena
OSTI ID:
5299735
Country of Origin:
United Kingdom
Language:
English
Other Identifying Numbers:
Journal ID: CODEN: JATPA
Submitting Site:
INIS
Size:
Pages: 787-792
Announcement Date:
Feb 01, 1978

Citation Formats

Muraoka, Y, Murata, H, and Sato, T. Quantitative relationship between VLF phase deviations and 1-8 A solar X-ray fluxes during solar flares. United Kingdom: N. p., 1977. Web. doi:10.1016/0021-9169(77)90140-4.
Muraoka, Y, Murata, H, & Sato, T. Quantitative relationship between VLF phase deviations and 1-8 A solar X-ray fluxes during solar flares. United Kingdom. doi:10.1016/0021-9169(77)90140-4.
Muraoka, Y, Murata, H, and Sato, T. 1977. "Quantitative relationship between VLF phase deviations and 1-8 A solar X-ray fluxes during solar flares." United Kingdom. doi:10.1016/0021-9169(77)90140-4. https://www.osti.gov/servlets/purl/10.1016/0021-9169(77)90140-4.
@misc{etde_5299735,
title = {Quantitative relationship between VLF phase deviations and 1-8 A solar X-ray fluxes during solar flares}
author = {Muraoka, Y, Murata, H, and Sato, T}
abstractNote = {An attempt is made to investigate the quantitative relationship between VLF phase deviations in SPA (sudden phase anomalies) events and associated solar X-ray fluxes in the 1 to 8 A band during solar flares. The phase deviations (..delta..phi) of the 18.6 kHz VLF wave transmitted from NLK, USA are used in this analysis which were recorded at Nishinomiya, Japan during the period June 1974 to May 1975. The solar X-ray fluxes (F/sub 0/) in the 1 to 8 A band are estimated from fsub(min) variations using the empirical expression given by Sato (J.Geomag.Geoelectr.;27: 95(1975)), because no observed data were available on the 1 to 8 a X-ray fluxes during the period of the VLF observation. The result shows that the normalized phase variation, ..delta..phi/coschisub(min), where chisub(min) represents the minimum solar zenith angle on the VLF propagation path, increases with increasing logF/sub 0/. A theoretical explanation for this is presented assuming that enhanced ionizations produced in the lower ionosphere by a monochromatic solar X-ray emission are responsible for the VLF phase deviations. Also it is found that a threshold X-ray flux to produce a detectable SPA effect is approximately 1.5 x 10/sup -3/ cm/sup -2/ sec/sup -1/ in the 1 to 8 a band.}
doi = {10.1016/0021-9169(77)90140-4}
journal = {J. Atmos. Terr. Phys.; (United Kingdom)}
volume = {39:7}
journal type = {AC}
place = {United Kingdom}
year = {1977}
month = {Jul}
}