The August 2018 Geomagnetic Storm Observed by the High-Energy Particle Detector on Board the CSES-01 Satellite

Abstract

On 25 August 2018, a G3-class geomagnetic storm reached the Earth’s magnetosphere, causing a transient rearrangement of the charged particle environment around the planet, which was detected by the High-Energy Particle Detector (HEPD) on board the China Seismo-Electromagnetic Satellite (CSES-01). We found that the count rates of electrons in the MeV range were characterized by a depletion during the storm’s main phase and a clear enhancement during the recovery caused by large substorm activity, with the key role played by auroral processes mapped into the outer belt. A post-storm rate increase was localized at L-shells immediately above ∼3 and mostly driven by non-adiabatic local acceleration caused by possible resonant interaction with low-frequency magnetospheric waves.

Time Dependence of 50–250 MeV Galactic Cosmic-Ray Protons between Solar Cycles 24 and 25, Measured by the High-energy Particle Detector on board the CSES-01 Satellite

“…The payload is optimized to measure electrons in the 3-100 MeV energy range, and protons between ∼40 and 250 MeV, as well as light nuclei with a ±60°field of view and a geometrical acceptance of more than 400 cm 2 sr. The HEPD-01 capabilities for galactic and trapped protons and space weather studies have already been assessed in Bartocci et al (2020), Martucci et al (2022), Palma et al 2021, andin Piersanti et al (2022). More technical details on the mission and the instrument itself can be found in previous publications (Picozza et al 2019;Ambrosi et al 2020;Sotgiu et al 2020;Ambrosi et al 2021).…”

On the Magnetosphere‐Ionosphere Coupling During the May 2021 Geomagnetic Storm

“…Panels (c and d) in Figure 6 contain MEPED fluxes over the >0.65 MeV range and the rate of >4.5 MeV particles detected by HEPD‐01,respectively. At L shells typical of the ORB, a persistent depletion starts right after the onset of the main phase, with no short‐term flux recovery to pre‐storm levels (Palma et al., 2021, and reference therein). These ORB losses in the relativistic range may be consistent with magnetopause shadowing (Herrera et al., 2016) and outward radial transport, as suggested by a deep incursion of the magnetopause, as estimated from the Shue et al.…”

“…In order to evaluate the rearrangement of electron populations in the Earth's magnetosphere, we have applied an approach analogous to the one reported in Palma et al. (2021) for the 26 August 2018 geomagnetic storm, using particle data from the MEPED‐90° electron telescope on board the NOAA19‐POES satellite (Evans & Greer, 2004) and the High‐Energy Particle Detector (HEPD‐01) on board the CSES satellite (Picozza et al., 2019). The NOAA19‐POES is Sun‐synchronous nearly‐polar satellite orbiting at LEO altitudes.…”

On the magnetosphere-ionosphere coupling during the May 2021 Geomagnetic storm.

“…In order to evaluate the rearrangement of electron populations in the Earth's magnetosphere, we have applied an approach analogous to the one reported in Palma et al (2021) for the 26 August 2018 geomagnetic storm, using particle data from the MEPED-90° electron telescope on board the NOAA19-POES satellite (Evans & Greer, 2004) and the High-Energy Particle Detector (HEPD-01) on board the CSES satellite (Picozza et al, 2019). The NOAA19-POES is Sun-synchronous nearly-polar satellite orbiting at LEO altitudes.…”