Direct modeling of neutral helium in the heliosphere

TL;DR

This paper introduces a detailed computational method to model neutral helium in the heliosphere, accounting for particle creation and loss, aiding interpretation of spacecraft measurements and understanding interstellar medium properties.

Contribution

It presents a conserving calculation approach based on Keplerian orbits for modeling helium distribution functions within the heliosphere, integrating plasma models for accurate flux predictions.

Findings

Effective modeling of neutral helium distribution in the heliosphere

Improved predictions of neutral atom fluxes at spacecraft detectors

Enhanced understanding of interstellar medium characteristics

Abstract

Several years of neutral particle measurements by the NASA/IBEX mission have yielded direct observations of interstellar neutral helium and oxygen. The data indicate the presence of secondary neutral helium and oxygen, which are created within the heliosphere by charge exchange involving helium or oxygen ions. This contribution describes a detailed conserving calculation method based on Keplerian orbits that has been developed to characterize helium distribution functions throughout the heliosphere, in particular in the innermost heliosphere, while accounting for loss and production of neutral particles along their path. Coupled with global heliosphere models of plasma distributions, this code is useful for predicting the fluxes of heavy neutral atoms at spacecraft detectors, so enabling inferences on the characteristics of the interstellar medium.