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G. L. S. S. Liyanage

Publications and source records attributed to G. L. S. S. Liyanage.

2 recordsLinked to original sources

e-CALLISTO FITS Analyzer: A Software Framework for CALLISTO Solar Radio Data

Solar radio bursts are important signatures of dynamic processes in the solar corona, including particle acceleration and shock propagation associated with solar flares and coronal mass ejections. Among the missions that report solar radio bursts within 24 hours, the e-CALLISTO archive is the largest, with more than 150 stations worldwide. The archive generates large volumes of FITS data that are often affected by radio-frequency interference and background noise. Irregular frequency setups in different stations are also a limitation of statistical analysis of SRBs. Each CALLISTO observation is a 15-minute frame, which often causes a single burst to split over multiple frames, making event-level analysis difficult. This work presents the e-CALLISTO FITS Analyzer, a unified, interactive, cross-platform application for processing and analyzing e-CALLISTO dynamic spectra on Windows, macOS, and Linux. The application supports time and frequency merging to produce a continuous spectrum, applies mean background subtraction with user-controlled threshold clipping, and isolates burst regions through an interactive polygon mask in the time-frequency plane. It also extracts the maximum-intensity backbone, allows interactive outlier removal, and performs power-law fitting to estimate drift rates and derive shock height and speed using the Newkirk model, including $n$-fold scaling. For a Type II burst observed by Arecibo Observatory on 2 March 2022, the analyzer yielded an average drift rate of $-0.0400 \pm 0.0003\, MHz/s$ and an average shock speed of $449 \pm 1\, km/s$ at a height of $1.715 \pm 0.002\, R_{\odot}$. The e-CALLISTO FITS Analyzer supports more reproducible, event-focused SRB analysis and improves access to physically meaningful measurements from e-CALLISTO FITS data.

astro-ph.SR↗

Determination of Speed and Source Height of Coronal Shock Waves Using Type II Solar Radio Bursts

This study examines the shock speed and source height of coronal shock waves using Type II solar radio bursts. The solar radio burst data from January 2022 to October 2023 were obtained from eCALLISTO archive. The type II radio bursts were isolated from the spectra through a rigorous noise reduction process by taking the maximum intensity of each time channel. Using plasma oscillations and electron density models for the solar corona, explicit expressions for shock speed and source height were obtained. From the dynamic spectra, the starting frequency of a burst was obtained and using these parameters shock speed and source height were calculated. Results confirmed shock speeds ranging from 343 to 1032 kms$^{-1}$ with average speed of 650$\pm$226 kms$^{-1}$ and source heights 1.317-1.724 R$_\odot$, with high precision in formula predictions. The study highlights the need for broader burst type inclusion in future research and underscores the efficacy of the developed methodologies to improve space weather forecasts.

astro-ph.SR↗