Interstellar medium parameters in front of the external bow shock

TL;DR

This paper generalizes equations describing the external bow shock region to better understand interstellar medium parameters using spacecraft data, enhancing physical insights into the heliosphere boundary.

Contribution

It extends previous models to the external bow shock, enabling more accurate estimation of interstellar medium parameters from spacecraft measurements.

Findings

Derived new relationships for external bow shock parameters

Potential to estimate interstellar medium properties with enhanced spacecraft data

Improved understanding of heliosphere boundary processes

Abstract

We know that it is the front of the bow shock where the solar wind kinetic energy flux is transformed into the other kinds the most intensively. In our previous studies, we obtained important relationships that enable calculating the key parameters at transition through the bow shock front. One of the most important sources of information on physical processes at the heliosphere boundary are the Voyager 1 and 2 spacecrafts. Since both the solar wind and interstellar medium are supersonic streams, two shocks are formed when flowing around the heliopause. The internal shock, in which the solar wind decelerates to subsonic velocity, is called the heliospheric shock. In the external bow shock, the interstellar gas supersonic flux is decelerated. The aim of this paper is to generalize the previously obtained equations to the processes in the external bow shock region. If Voyager-1 was equipped with a greater set of measuring instruments, we could have already provided estimations of the interstellar medium key parameters, and described in physical terms what this medium is, using relationships and equations from our studies.