Long term features of geomagnetically trapped particles

GUTIERREZ FALCON, ALVARO R.; ZOSSI, BRUNO S.; AMIT, HAGAY; ELIAS, ANA G.

Nagoya

Workshop; PWING-ERG Conference; 2021

ISEE, Nagoya University

The trajectory of energetic particles trapped by the geomagnetic field is usually defined by three cyclic motions: gyration, bounce along field lines, and drift around the earth, which are all controlled by this field. The geomagnetic field, in turn, has been declining at a rate of ~5% every hundred years since at least ~1840. A possible future scenario is a steady decrease of the dipole component with a field complexity increase through the relative growth of non-dipolar components. The expected variations in trapped particle trajectories, which describe an overall drift shell, is analyzed in the present work through an analytical approach helped by computer simulations using the Rice Adaptive Particle Tracer (RAPT) that is a Python framework for tracing relativistic charged particles in general electromagnetic fields. The main results are the decrease of drift shells mean distance to the Earth, decrease of mirror point altitudes, increase of conjugate mirror points asymmetry, and the split of radiation belts for pure multipolar configurations. The idealized and simplified structures here analyzed could shed light on the study of plausible radiation belt enhancements during polarity transitions which can have wide-range implications for man-made technologies that operate in space.