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Using geomagnetic birefringence to locate sources of impulsive, terrestrial VHF signals detected by satellites on orbit
Author(s) -
Jacobson Abram R.,
Shao XuanMin
Publication year - 2001
Publication title -
radio science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.371
H-Index - 84
eISSN - 1944-799X
pISSN - 0048-6604
DOI - 10.1029/2000rs002555
Subject(s) - earth's magnetic field , ionosphere , physics , satellite , signal (programming language) , birefringence , radio wave , optics , remote sensing , geophysics , magnetic field , geology , astronomy , computer science , quantum mechanics , programming language
The Earth's ionosphere is magnetized by the geomagnetic field and imposes birefringent modulation on VHF radio signals propagating through the ionosphere. Satellites viewing VHF emissions from terrestrial sources receive ordinary and extraordinary modes successively from each broadband pulse emitted by the source. The birefringent intermode frequency separation can be used to determine the value of ƒ ce cos β, where ƒ ce is the electron gyrofrequency and β is the angle between the wave vector k and the geomagnetic field B at the point where the VHF ray path intersects the ionosphere. Successive receptions of multiple signals (from the same source) cause variation in ƒ ce cos β, and from the resulting variation in the signal intermode frequency separation the source location on Earth can be inferred. We test the method with signals emitted by the Los Alamos Portable Pulser and received by the FORTE satellite.