# Plasma pressures in the heliosheath from Cassini ENA and Voyager 2 measurements: Validation by the Voyager 2 heliopause crossing

## TL;DR

This study combines in-situ and remote sensing measurements from Voyager 2 and Cassini to analyze plasma pressures in the heliosheath, validating models of interstellar conditions and heliopause location.

## Contribution

It provides a novel integrated analysis of ion and ENA measurements to estimate interstellar parameters and heliopause crossing, validating pressure-based models with in-situ data.

## Key findings

- Estimated interstellar neutral hydrogen density of ~0.12 cm-3
- Interstellar magnetic field strength of ~0.5 nT
- Voyager 2 heliopause crossing at ~119 AU

## Abstract

We report "ground truth", 28-3500 keV in-situ ion and 5.2-55 keV remotely sensed ENA measurements from Voyager 2/Low Energy Charged Particle (LECP) detector and Cassini/Ion and Neutral Camera (INCA), respectively, that assess the components of the ion pressure in the heliosheath. In this process, we predict an interstellar neutral hydrogen density of ~0.12 cm-3 and an interstellar magnetic field strength of ~0.5 nT upstream of the heliopause in the direction of V2, i.e. consistent with the measured magnetic field and neutral density measurements at Voyager 1 from August 2012, when the spacecraft entered interstellar space, to date. Further, this analysis results in an estimated heliopause crossing by V2 of ~119 AU, as observed, suggesting that the parameters deduced from the pressure analysis are valid. The shape of the >5.2 keV ion energy spectra play a critical role towards determining the pressure balance and acceleration mechanisms inside the heliosheath.