Charged particle scattering in dipolarized magnetotail

The earth's magnetotail is characterized by stretched magnetic field lines. Energetic particles are effectively scattered due to the field-line curvature, which then leads to isotropization of energetic particle distributions and particle precipitation to the earth's atmosphere. Measurements of precipitation at low-altitude spacecrafts are, thus, often used to remotely probe the magnetotail current sheet configuration. This configuration may include spatially localized maxima of the curvature radius at the equator (due to localized humps of the equatorial magnetic field magnitude) that reduces the energetic particle scattering and precipitation. Therefore, precipitation patterns are related to the spatial profiles of the equatorial curvature radius that is further determined by the magnetotail current sheet configuration. In this study, we show that, contrary to previous thoughts, the magnetic field line configuration with the localized curvature radius maximum can actually enhance the scattering and subsequent precipitation. The spatially localized magnetic field dipolarization (magnetic field humps) can significantly curve magnetic field lines far from the equator and create off-equatorial minima in the curvature radius. Scattering of energetic particles in these off-equatorial regions alters the scattering (and precipitation) patterns, which has not been studied yet. We discuss our results in the context of remote-sensing the magnetotail current sheet configuration with low-altitude spacecraft measurements.& nbsp;(C)2021 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license(http://creativecommons.org/licenses/by/4.0/)