Automatic Whistler Detector and Analyzer system: Implementation of the analyzer algorithm

Abstract

[1] The full potential of whistlers for monitoring plasmaspheric electron density variations has not yet been realized. The primary reason is the vast human effort required for the analysis of whistler traces. Recently, the first part of a complete whistler analysis procedure was successfully automated, i.e., the automatic detection of whistler traces from the raw broadband VLF signal was achieved. This study describes a new algorithm developed to determine plasmaspheric electron density measurements from whistler traces, based on a Virtual (Whistler) Trace Transformation, using a 2-D fast Fourier transform transformation. This algorithm can be automated and can thus form the final step to complete an Automatic Whistler Detector and Analyzer (AWDA) system. In this second AWDA paper, the practical implementation of the Automatic Whistler Analyzer (AWA) algorithm is discussed and a feasible solution is presented. The practical implementation of the algorithm is able to track the variations of plasmasphere in quasi real time on a PC cluster with 100 CPU cores. The electron densities obtained by the AWA method can be used in investigations such as plasmasphere dynamics, ionosphere-plasmasphere coupling, or in space weather models.

Measurements of atmospheric electricity in the Széchenyi István Geophysical Observatory, Hungary

“…Note that the chimney is not functioning. graphical processing unit (GPU) cards (Lichtenberger et al, 2013). Results of the whistler analysis, including data from Nagycenk, have been published by Koronczay et al (2019).…”

VLF Transmitters as Tools for Monitoring the Plasmasphere

“…We consulted Jacobsen (), Jaatinen (), and Balov and Zarubin () for basic information. In addition, we made VLF measurements at three AWDANet VLF receiver ground stations (Lichtenberger et al, , ): at Tihany, Hungary; Tvarminne, Finland; and Karymshina in Kamchatka, Russia (all within 2,000‐km distance of an Alpha transmitter) to confirm the Alpha transmission sequences and to determine their exact timing.…”

“…This same inversion process is used, for example, for whistler inversion, a standard tool for acquiring plasmaspheric electron densities. It forms the basis of a recent global ground‐based network for automatic detection and inversion of whistlers (AWDANet, see Lichtenberger et al, and Lichtenberger et al, ). Second, this method escapes some of the limitations of other electron density measurements, for example, those derived from plasma resonance frequencies measured by EMFISIS on the Van Allen Probes satellites (Kurth et al, ) and by WHISPER on the CLUSTER satellites (Décréau et al, ; Kougblénou et al, ).…”

Remote sensing of D-region ionosphere using multimode tweeks

“…The arrival times (t 1 and t 2 ) of sferics of frequencies (f 1 and f 2 ) could be read from spectrograms as well to determine propagation distance (d) of the tweeks. The details of AWD software and the MATLAB program for AWD analysis could be obtained from [33,34].…”