Authors: Xiaohan Ma (Boston University), Merav Opher (Boston University)

The heliosphere is a vast region surrounding the Sun that marks the outer limits of the solar wind. It is formed due to the interaction between the solar wind and the partially ionized gas of the local interstellar medium. Due to the solar magnetic field, the heliosheath can flow into distinct north and south jets. Opher et. al. (2021) found the interaction of neutral H atoms streaming from the ISM with the ionized matter in the heliosheath will act as an effective gravity, causing the Rayleigh–Taylor instability to develop along the axis of the jets. The instability destroys the coherence of the heliospheric jets and magnetic reconnection ensues, allowing interstellar medium material to penetrate the heliospheric tail. Here we present a review of Opher et. al. (2021), which modeled thermal solar wind ions and pick-up ions as a single-ion plasma, showing the driver of the turbulence in the heliosheath. We will also discuss the on-going work about the Rayleigh–Taylor instability development with a multi-ion model (Opher et al. 2020), where the cooler thermal solar wind ions and the hotter PUIs are treated as separate fluids.