Numerical simulation of equatorial ionospheric response to extra-terrestrial high energy phenomena using ion chemistry models
Tipo
Capítulo de livro
Data de publicação
2018
Periódico
Astrophysics and Space Science Proceedings
Citações (Scopus)
0
Autores
Palit S.
Orientador
Título da Revista
ISSN da Revista
Título de Volume
Membros da banca
Programa
Resumo
© Springer International Publishing AG, part of Springer Nature 2018.Ionosphere of earth is a giant natural plasma laboratory, which responses to various excitations from local and celestial radiation sources. Apart from the ever-present cosmic rays and the day-time ultraviolet radiation from the Sun, solar activities modify the plasma environment of the ionosphere with frequency regulated by the 11-year solar cycle. While incident energetic charged particles from events like solar flares and coronal mass ejections (CMEs), lead by geomagnetic field, affect only the high latitude part of the ionosphere, the equatorial ionosphere is readily modified due to ionization by the enhanced high energy photons, such as, extreme ultraviolet (EUV), soft X-ray fluxes etc. Evaluation of the modulation in ionospheric plasma properties by such events requires detailed estimation of the altitude-wise energy deposition/ionization rates and the subsequent ion-chemistry evolution. Particularly the least explored lowest part of the ionosphere (called the D-region during day time), for which direct evaluation of any physical parameters is almost impossible and radio frequency remote sensing is the only viable option, the task is quite challenging. A new computer model comprising of Monte Carlo simulation and a simplistic ion-chemistry scheme to evaluate the effect of extra-terrestrial ionizing radiation sources on D-region ionosphere is presented here. Rigorous validation of the model by comparing the outcome with Very Low Frequency (VLF) radio wave studies of several solar flares in a propagation path belonging to Indian subcontinent is done. The model is also extended to explore a reconstruction method to find source characteristics, like spectrum of incident photons by deconvolution of the observed plasma parameters. This is a significant stride along the path to establish earth’s atmosphere as an astronomical detector.
Descrição
Palavras-chave
Assuntos Scopus
Coronal mass ejection , Energetic charged particles , Equatorial ionosphere , Extreme ultraviolets , Indian subcontinents , Ionospheric plasmas , Reconstruction method , Source characteristics