CSES monitoring of the interplay between current-sheet and EMIC-wave driven scattering as a proxy of substorm activity

Plasma injections from Earth’s magnetotail to high-latitude ionosphere pro-
vided by substorm activity are known to play a key role in the MeV-electron
acceleration mechanism by resonating interaction of very-low-frequency (VLF)
chorus waves with seed electrons. On the other hand, non-adiabatic motion
of plasma-sheet protons related to current sheet scattering (CSS) causes pitch-
angle diffusion and precipitation to the ionosphere, inducing the formation of
a characteristic energy-latitude dispersion pattern at the equatorward side of
the auroral isotropy boundary (IB), which gets significantly altered during geo-
magnetic storms due to particle precipitation triggered by electromagnetic ion
cyclotron (EMIC) waves.
For these last two years, a moderate geomagnetic storm activity has been affect-
ing the Earth’s environment, with the notable case of Aug 2018 G3-class storm.
The effects of such disturbances - especially in case of prolonged substorm ac-
tivity during the recovery phase - have been clearly spotted by the entire suite
of detectors on board the China Seismo-Electromagnetic Satellite (CSES-01), a
low-Earth-orbit (LEO) mission launched on Feb 2, 2018.
Here, we present long-term storm-time observations by particle, e.m.-field, and
plasma instrumentation on board CSES-01, namely the High-Energy Particle
Detector (HEPD), the Electric Field Detector (EFD), and the High Precision
Magnetometer (HPM), either developed or data-validated by the Italian LI-
MADOU Collaboration. Thanks to magnetosphere-to-ionosphere mapping, re-
sults from HEPD, EFD, and HPM data analysis help track substorm plasma
injections and consequent magnetosphere re-arrangement on a statistical basis.
This further inscribes CSES-01 into the thematic area of space-weather and
space-climate exploration and modeling, which is especially important in a pe-
riod when many key space-weather instruments have been quit or operate well
beyond the end of their scheduled lifetimes.