Study and modeling the effects of solar flares and high-energy SGR/GRB transient events on the Earths ionosphere

• Grant number: 16/02550-6
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Effective date (Start): March 01, 2017
• Effective date (End): February 28, 2019
• Field of knowledge: Physical Sciences and Mathematics - Geosciences - Geophysics
• Acordo de Cooperação: Coordination of Improvement of Higher Education Personnel (CAPES)
• Principal Investigator: Jean Pierre Raulin
• Grantee: Sourav Palit
• Host Institution: Escola de Engenharia (EE). Universidade Presbiteriana Mackenzie (UPM). Instituto Presbiteriano Mackenzie. São Paulo , SP, Brazil
• Associated research grant: 13/24155-3 - Solar flare diagnostic in an unprecedented frequency range from microwaves to THz frequencies: challenges for interpretation (flat), AP.TEM

Abstract

Earth's upper atmosphere and ionosphere are constantly penetrated by ionizing radiation from various high energetic extra-terrestrial events, such as solar flares, energetic particle events, Soft Gamma Repeater (SGR), Gamma Ray Bursts (GRB) etc. In low and mid-latitude region of the ionosphere, where the entrance of most of the particles are restricted by high geomagnetic cut-off, the X-ray and Gamma ray photons produce most of the ionization. Resulting changes in plasma parameters, such as electron and ion densities are readily manifested in Very Low Frequency (VLF) signal, which propagates in Earth-ionosphere waveguide. The dependence of VLF wave propagation characteristics on multiple ionospheric parameters, such as electron density, collision frequency etc. and modal-interference between VLF waves make the interpretation of such modulation challenging. In this study using South America VLF Network (SAVNET) data we will try to analyse and model the effects of various astronomical transients sources on the lower ionosphere and atmosphere below it and the VLF propagation. This study is immensely important in further advancement in the knowledge of interaction of Earth's atmosphere with solar and other extra-terrestrial phenomena, estimating the risk-factor from such events and establishing Earth's ionosphere and atmosphere as a whole, as the detector of astronomical sources. (AU)

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

PALIT, SOURAV; RAULIN, JEAN-PIERRE; CORREIA, EMILIA. Lower Ionospheric Plasma-Chemical Evolution and VLF Signal Modulation by a Series of SGR X-Ray Bursts: Numerical Simulation With an Ion-Chemistry Model. JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS, v. 123, n. 9, p. 7930-7942, SEP 2018. (16/02550-6)