Characterization of the lower ionosphere response to solar transients.

• Grant number: 10/05309-1
• Support type: Scholarships in Brazil - Doctorate
• Effective date (Start): August 01, 2010
• Effective date (End): February 28, 2013
• Field of knowledge: Physical Sciences and Mathematics - Geosciences
• Principal researcher: Emilia Correia
• Grantee: Hernan Rivero Gavilan
• Home Institution: Centro de Rádioastronomia e Astrofísica Mackenzie (CRAAM). Universidade Presbiteriana Mackenzie (UPM). Instituto Presbiteriano Mackenzie. São Paulo , SP, Brazil

Abstract

One of the consequences of solar flares in the ionosphere is the sudden increase of electron concentration in the D-region, which is detected as advances in phase of the VLF signals, the so-called 'Sudden Phase Anomalies' (SPAs). It is also known that over 18% of solar flares recorded not produce SPAs, there are few studies that could explain the reasons for this fact. Changes in the electrical properties of the D-region when occurring SPAs permit compute the effective recombination coefficients for altitudes lower than 70 km. In this project we propose to study the ionospheric response (SPA) from the flux of solar radiation (J/m2) for wavelengths shorter than 2 Å and its emission measure (EM), calculated from the flux in X-rays obtained by the GOES satellite and SPA recorded by the SAVNET (South America VLF Network) since the beginning of its operation in 2006. In addition, characterize the processes of electron loss by calculating the effective recombination coefficient for several paths of VLF propagation.