# Solar Energetic Particle transport near a Heliospheric Current Sheet

## TL;DR

This study investigates how a flat Heliospheric Current Sheet influences Solar Energetic Particle transport, revealing significant drift effects, complex time profiles, and the impact of IMF configuration on proton propagation.

## Contribution

It introduces a detailed 3-D simulation of proton propagation near a flat HCS, highlighting the effects of current sheet drift and IMF configuration on SEP transport.

## Key findings

- Protons experience significant drift causing multiple time profile components.
- Variation in current sheet thickness has minimal impact on particle propagation.
- A flat HCS limits proton crossing into the opposite hemisphere.

## Abstract

Solar Energetic Particles (SEPs), a major component of space weather, propagate through the interplanetary medium strongly guided by the Interplanetary Magnetic Field (IMF). In this work, we analyse the implications a flat Heliospheric Current Sheet (HCS) has on proton propagation from SEP release sites to the Earth. We simulate proton propagation by integrating fully 3-D trajectories near an analytically defined flat current sheet, collecting comprehensive statistics into histograms, fluence maps and virtual observer time profiles within an energy range of 1--800 MeV. We show that protons experience significant current sheet drift to distant longitudes, causing time profiles to exhibit multiple components, which are a potential source of confusing interpretation of observations. We find that variation of current sheet thickness within a realistic parameter range has little effect on particle propagation. We show that IMF configuration strongly affects deceleration of protons. We show that in our model, the presence of a flat equatorial HCS in the inner heliosphere limits the crossing of protons into the opposite hemisphere.