ALBERT

Description: The investigation of heavy ions dynamics and properties in the Earth's magnetosphere is still an important field of research as they play an important role in several space weather aspects. We present a statistical survey of the average ion mass in the dayside magnetosphere made comparing plasma mass density with electron number density measurements and focusing on both spatial and geomagnetic activity dependence. Field line resonance frequency observations across the European quasi-Meridional Magnetometer Array, are used to infer the equatorial plasma mass density in the range of magnetic L-shells 1.6–6.2. The electron number density is derived from local electric field measurements made on Van Allen Probes using the Neural-network-based Upper-hybrid Resonance Determination algorithm. The analysis is conducted separately for the plasmasphere and the plasmatrough during favorable periods for which both the plasma parameters are observed simultaneously. We found that throughout the plasmasphere the average ion mass is ≃1 amu for a wide range of geomagnetic activity conditions, suggesting that the plasma mainly consist of hydrogen ions, without regard to the level of geomagnetic activity. Conversely, the plasmatrough is characterized by a variable composition, highlighting a heavy ion mass loading that increases with increasing levels of geomagnetic disturbance. During the most disturbed conditions, the average radial structure shows a broad maximum around 3–4 Earth radii, probably correlated with the accumulation of oxygen ions near the plasmapause. Those ions are mostly observed in the post-dawn and pre-dusk longitudinal sectors.

Description: FARBES (Forecast of Radiation Belt Scenarios) is a recently started H2020 project to predict the subsequent behavior of a geomagnetic storm after its arrival. For such predictions, FARBES intends to use only ground-based, real-time data to produce input parameters of the radiation belt model, like Salammbô. These input parameters are 1. Outer boundary (magnetopause boundary and injected distribution from the plasmasheet); 2. Background plasma density; 3. Amplitudes of natural waves and their distribution (Chorus, Hiss, EMIC, lightning-whistlers); 4. Amplitude and distribution of radial diffusion coefficients; 5. The low energy boundary condition. Here we focus on the third input data, the ‘Amplitudes of natural waves and their distribution.’ To get the specifications of the in situ natural wave environment, we created an empirical transfer function to describe the attenuation/amplification of whistler-mode waves during their quasi-parallel propagation from the equator through the ionosphere to the ground. We used whistler-mode waves from satellites, like Van Allen Probes, Cluster, and DEMETER, and the ground-based VLF recordings of AWDANet. For this study, we selected the 0.1-0.9 fce (giro-frequency) frequency range of the spectrograms to calculate the average wave powers. Ground-based spectrograms required extensive noise removal (sferics, hum harmonics, etc.) considering the daily attenuation variation of the Earth-Ionosphere waveguide.