POLARIZATION OF VLF ATMOSPHERICS NEAR THE RESONANCE FREQUENCY OF EARTH – IONOSPHERE WAVEGUIDE BY OBSERVATIONS IN THE AURORAL REGION

• Main Authors: A. A. Ostapenko, E. E. Titova, T. Turunen, J. Manninen, T. Raita
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Northern Finland
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.539.7321; http://pgia.ru/seminar/archive/2008/3_waves/ostapenko_a_a.pdf

Abstract. Ground-based recording of ELF-VLF waves with right-handed (R) and left-handed (L) circular polarization has been performed at the frequency range of 0-10 kHz in Northern Finland. Monitoring showed a difference in the behavior of VLF waves with R- and L-polarization. The waves with a perfect circular L-polarization were observed at and just above the Earth-ionosphere waveguide cutoff frequency, which is the critical frequency of the first transverse resonance in Earth-ionosphere waveguide (around 1.6-2.3 kHz). To study the features of VLF wave propagation near the mode cutoff frequencies, we derived the attenuation of VLF waves with right (R)- and left (L)-polarization from the full wave equation for different models of the ionosphere. Our calculations show that a maximum in the spectra of VLF waves near the critical frequencies of 1.6 – 2.3 kHz due to small absorption of L waves and excitation of resonance waves in Earth – ionosphere waveguide.