The Swarm mission high energy particle flux investigation

Swarm mission constellation, launched into orbit on November 22, 2013, consists of three satellites that precisely measure magnetic signal of the Earth using the ASM and VFM, integrated with three Advanced Stellar Compass star trackers cameras. By using a minimum of magnetic material close to the magnetometer sensors (optimal for the magnetic measurements), the resulting shielding is insufficient to stop the more energetic part of the particle flux encountered in the Swarm constellation orbit, where protons above 60MeV and electrons above 10MeV may penetrate to the focal plane detectors.

To eliminate the ASC cameras sensitivity to passing energetic particles, the ASC employ a suite of morphological filters removing the effects from such particles before the stars observed are matched to the onboard catalogue. The efficacy of these filters is high enough to ensure full performance even during the most intense CMEs, moreover, the measured rate of these penetrating particles, effectively monitors the high energy particle flux.

Since May 2018, the spacecraft thus have sent the measured fluxes to ground, enabling very precise map of this part of the energetic flux. World map of the AP-8 MAX integral proton flux >10 MeV at 500 km altitude (Heynderickx, 1996) Particles flux for Swarm spacecrafts Ionizing particles in the Swarm orbits DTU Space μASC We present world maps of the energetic particle flux, its variation with altitude, local time, direction and seasonal variations.

We further present a view of the dynamic part of the flux, from injection sources such as CMEs, which gives a detailed profiling of the direction, injection time scales and relaxation times.