Weighted CRAND injection coefficients at Saturn
Abstract
The Cosmic Ray Albedo Neutron Decay (CRAND) process is considered as a main source process for high energy proton component of the radiation belts of Saturn, what was confirmed by Cassini Magnetospheric Imaging Instrument (MIMI) observations. The layered structure of the main radiation belt of Saturn with the clear depletions on the L-shells corresponding to the location of the moons and the existence of the innermost radiation belt, residing between the atmosphere of the planet and the Main Rings (Roussos et al., 2018) can be explained only by the presence of the local source of the energetic ions like CRAND.
We study the CRAND process at Saturn and in order to evaluate its efficiency we calculated the so-called injection coefficients, which determine the fraction of ejected neutrons with the correct geometrical propagation such that they can have the possibility to contribute to the belts' population. We evaluate the relative contribution of the different source areas on the rings at the atmosphere and for different angular source emission functions for the neutrons, which convert into the protons that sustain the radiation belts. The primary galactic cosmic rays (GCR) access to the Saturnian system which initiate the CRAND we calculated using the particle tracing method on the base of the realistic magnetospheric model (Kotova et al., 2019). The neutrons production from the interaction of GCR with the material of the rings and atmosphere was estimated using the GEANT (GEometry ANd Tracking) simulation, which model flux spectra of protons, electrons, positrons, charged pions, neutrons, and gamma ray photons emitted from GCR interactions with rings or atmospheric matter (Cooper et al., 2018). We also consider the possibility of the multiple cascades of secondaries between the atmosphere and the rings. We will also discuss how the CRAND process can work at other outer planets environment such as Uranus and Neptune.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFMSM33C3214K
- Keywords:
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- 2756 Planetary magnetospheres;
- MAGNETOSPHERIC PHYSICS;
- 2774 Radiation belts;
- MAGNETOSPHERIC PHYSICS;
- 2780 Solar wind interactions with unmagnetized bodies;
- MAGNETOSPHERIC PHYSICS;
- 2784 Solar wind/magnetosphere interactions;
- MAGNETOSPHERIC PHYSICS