TY - JOUR
T1 - Anomalously strong vertical magnetic fields from distant ELF/VLF sources
AU - Silber, Israel
AU - Price, Colin
AU - Galanti, Eli
AU - Shuval, Abraham
N1 - Publisher Copyright:
©2015. American Geophysical Union. All Rights Reserved.
Copyright:
Copyright 2015 Elsevier B.V., All rights reserved.
PY - 2015/7/1
Y1 - 2015/7/1
N2 - There are many sources of very low frequency (VLF - 3-30 kHz) and extremely low frequency (ELF - 3-3000 Hz) radiation in the Earth-ionosphere waveguide (e.g., lightning and ELF/VLF communication transmitters). At distances of thousands of kilometers from these sources, the vertical component of the ELF/VLF AC magnetic fields is expected to be very weak and several orders of magnitude lower than the horizontal magnetic components. However, measurements in Israel show a relatively strong vertical magnetic component in both the ELF and VLF bands, at the same order of magnitude as the horizontal components. Our measurements suggest that the real Earth-ionosphere waveguide might often be very different from the theoretical waveguide used in model calculations. In addition, our results imply that using only the horizontal components for direction finding or the absolute magnetic field strength may result in errors, since often a significant fraction of the magnetic field energy hides in the vertical component.
AB - There are many sources of very low frequency (VLF - 3-30 kHz) and extremely low frequency (ELF - 3-3000 Hz) radiation in the Earth-ionosphere waveguide (e.g., lightning and ELF/VLF communication transmitters). At distances of thousands of kilometers from these sources, the vertical component of the ELF/VLF AC magnetic fields is expected to be very weak and several orders of magnitude lower than the horizontal magnetic components. However, measurements in Israel show a relatively strong vertical magnetic component in both the ELF and VLF bands, at the same order of magnitude as the horizontal components. Our measurements suggest that the real Earth-ionosphere waveguide might often be very different from the theoretical waveguide used in model calculations. In addition, our results imply that using only the horizontal components for direction finding or the absolute magnetic field strength may result in errors, since often a significant fraction of the magnetic field energy hides in the vertical component.
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U2 - 10.1002/2015JA021141
DO - 10.1002/2015JA021141
M3 - Article
AN - SCOPUS:84940712455
VL - 120
SP - 6036
EP - 6044
JO - Journal of Geophysical Research: Space Physics
JF - Journal of Geophysical Research: Space Physics
SN - 2169-9380
IS - 7
ER -