Abstract :
–
The lower ionospheric D region is a dilute and weakly ionized plasma, very sensitive to external disturbances. Excesses of ionization due to X-rays or energetic particles produced during solar flares will change the local electrical conductivity, and result in propagation anomalies for Very Low Frequency (VLF) waves within the Earth-Ionosphere Waveguide (EIW). These appear as VLF phase and amplitude variations (Δφ, ΔA) at the receiver, and represent changes of the reference height (H’) and of the conductivity gradient or sharpness (β), both H’ and β also know as the Wait parameters. We present results obtained using the South America VLF NETwork (SAVNET) and will focus on the monitoring the long-term solar activity and shorter transient phenomena as solar flares or energetic bursts from remote cosmic objects. We will also draw particular attention to the diagnostic of the South Atlantic (Magnetic) Anomaly (SAMA or SAA), the use of the Terminator Time method, and the absorption of High Frequency (HF) waves during solar explosive events. Finally, we will describe upgrades which are being performed on SAVNET.
Remote sensing of the lower ionosphere D-region using the South America VLF NETwork (SAVNET)
Jeudi 1er octobre 2026
de
11:00 à
12:00
Bâtiment 17 - Salle de conférence / En ligne
