While voyager 1 is widely believed to be measuring the properties of the local interstellar medium (lism), voyager 2 is detecting the solar wind (SW) and heliospheric magnetic field (HMF) properties…

This federal contract award to the University of Alabama in Huntsville (UAH) is for research to investigate the fundamental properties of the solar wind-local interstellar medium interaction, with a focus on the role of non-thermal pickup ions. The $742,852.22 grant from the National Aeronautics and Space Administration (NASA) will support this research over the period ending on December 31, 2023. UAH is a public research university that provides a range of research and engineering services to federal agencies, including NASA, through contracts and grants. This award is not associated with a set-aside designation. The research aims to address key questions related to the solar system's boundary with interstellar space, as observed by the Voyager 1 and Voyager 2 spacecraft, and to validate theoretical models of the heliosphere.

While voyager 1 is widely believed to be measuring the properties of the local interstellar medium (lism), voyager 2 is detecting the solar wind (SW) and heliospheric magnetic field (HMF) properties in the inner heliosheath (IHS), which are markedly different from those observed by voyager 1 at the same heliocentric distance. The goal of this proposal to investigate the fundamental properties of the SW-lism interaction that are related to the presence of non-thermal, pickup ions (puis), are responsible for the spacecraft observations, and generate controversy in the literature related to physical processes occurring in the outer heliosphere. The questions that require definitive answers are the following: (1) what is the role of PUI in the stress balance at the heliopause? (2) how to implement genuinely kinetic boundary conditions for puis at the heliospheric termination shock in a way appropriate for a global-scale model capable of reproducing voyager and ibex observations? (3) what are the properties and physical consequences of microscopic turbulence produced by puis beyond the heliopause and how does IT relate to the macroscopic lism turbulence? (4) what is the origin of the heliospheric boundary layer (HBL, the region of depressed lism plasma density extending a few tens of AU beyond the heliopause), if IT exists even without the interstellar magnetic field (ismf)? (5) how can ibex and voyager measurements validate theoretical models of the heliosphere that take into account the effect of puis self-consistently?