Modeling the Time Dependent Interaction between the Solar Wind and the Local Interstellar Medium with Kinetic Neutral Hydrogen and Helium Atoms

Abstract We present recent advancements in our 3D modeling of the interaction between the solar wind and the local interstellar medium (LISM). The latest model results (Fraternale et al., ApJ, 2023) have raised a question about the electron density of the LISM near the heliopause. We have shown that the presence of helium ions leads to a significant underestimation of this parameter compared to the past simulations and Voyager 1 PWS observations. The latter observations, with over 12 years’ worth of LISM data, offers a robust constraint on our models. Here we present additional simulations in support of the idea that the LISM proton density may need to be revised from approximately 0.054 cm –3 to values around 0.07 cm –3 or higher. Additionally, we have developed and successfully tested a new version of the kinetic code suitable for simulating time-dependent solutions.