Matched filtering-parameter estimation method and analysis of whistlers recorded at Varanasi

R P SINGH¹, R P PATEL¹, ASHOK K SINGH¹, D HAMAR² and J LICHTENBERGER²

¹Atmospheric Research Laboratory, Physics Department, Banaras Hindu University,Varanasi 221 005, India

² Department of Geophysics, Eotvos University, Budapest, Hungary

Abstract.

The matched filtering technique is based on the digital-construction of theoretical whistlers and their comparison with observed whistlers. The parameters estimated from the theoretical and experimental whistler curves are matched to have higher accuracy using digital filters. This yields a resolution ten times better in the time domain. We have tested the applicability of this technique for the analysis of whistlers recorded at Varanasi. It is found that the whistlers have propagated along L > 2 and have wave normal angles after exiting from the ionosphere such that they propagate towards equator in the earth-ionosphere wave-guide. High-resolution analysis shows the presence of fine structures present in the dynamic spectrum. An effort is made to interpret the results.

Keywords: Matched filtering; fine structure; ducted mode propagation; banded whistlers.

Pacs No. 94.30.Tz