The Confinement of the Heliosheath Plasma by the Solar Magnetic Field as Revealed by Energetic Neutral Atom Simulations

Abstract

Traditionally, the solar magnetic field has been considered to have a negligible effect in the outer regions of the heliosphere. Recent works have shown that the solar magnetic field may play a crucial role in collimating the plasma in the heliosheath. Interstellar Boundary Explorer (IBEX) observations of the heliotail indicated a latitudinal structure varying with energy in the energetic neutral atom (ENA) fluxes. At energies ∼1 keV, the ENA fluxes show an enhancement at low latitudes and a deficit of ENAs near the poles. At energies >2.7 keV, ENA fluxes had a deficit within low latitudes, and lobes of higher ENA flux near the poles. This ENA structure was initially interpreted to be a result of the latitudinal profile of the solar wind during solar minimum. We extend the work of Kornbleuth et al. by using solar minimum–like conditions and the recently developed Solar-wind with Hydrogen Ion Exchange and Large-scale Dynamics (SHIELD) model. The SHIELD model couples the magnetohydrodynamic plasma solution with a kinetic description of neutral hydrogen. We show that while the latitudinal profile of the solar wind during solar minimum contributes to the lobes in ENA maps, the collimation by the solar magnetic field is important in creating and shaping the two high-latitude lobes of enhanced ENA flux observed by IBEX. This is the first work to explore the effect of the changing solar magnetic field strength on ENA maps. Our findings suggest that IBEX is providing the first observational evidence of the collimation of the heliosheath plasma by the solar magnetic field.

Signature of a heliotail organized by the solar magnetic field and the role of non-ideal processes in modeled IBEX ENA maps: a comparison of the BU and Moscow MHD models

“…These GDF maps also showed a similar profile to those observed by McComas et al (2013). Zirnstein et al (2017), Kornbleuth et al (2020), and Baliukin et al (2020) all produced modeled ENA maps of the heliosphere using different ENA models and different kinetic-MHD plasma solutions (with different boundary conditions) and were able to qualitatively reproduce the heliotail profile observed by IBEX-Hi.…”

“…In this section, we discuss the two kinetic-MHD models (BU and Moscow) used in this work (Section 2.1) and the ENA model prescription (Section 2.2). A more detailed description of the kinetic-MHD and ENA models can be found in Kornbleuth et al (2021) and Kornbleuth et al (2020), respectively.…”

Application of the Monte Carlo Method in Modeling Dusty Gas, Dust in Plasma, and Energetic Ions in Planetary, Magnetospheric, and Heliospheric Environments

“…TENISHEV ET AL. Valeille et al (2009aValeille et al ( , 2009b and Lee et al (2014aLee et al ( , 2014b Exosphere of the Moon Neutral particles, nonthermal population, the noninertial frame of reference that accounts for rotation of the Moon, the orbital motion of the Moon around the Earth, and the orbital motion of the Earth around the Sun; thermal accommodation at the Moon's surface, surface adsorption/desorption, volatile surface reservoir, photoionization Tenishev et al (2013) Coma of comet 67P/Churyumov-Gerasimenko Neutral particles, nonthermal population, irregularly shaped nucleus, photolytic reactions, internal degrees of freedom, interparticle collisions, gas/surface interaction Tenishev et al (2008), Fougere et al (2012Fougere et al ( , 2014Fougere et al ( , 2016, and Combi et al (2012Combi et al ( , 2020 Dust in a comet's environment Concurrent modeling of dust and gas, acceleration due to drag by the ambient gas Tenishev et al (2011Tenishev et al ( , 2016 Hydrogen population in the outer heliosphere Nonthermal population, interaction of the neutral hydrogen population with solar wind via charge exchange, production of the energetic neutral atoms (ENAs) via charge exchange reactions Kornbleuth et al (2020) Table 2 Summary of the Prior Applications of AMPS Figure 1. Example of a mesh used in simulations conducted using AMPS.…”

“…The global neutral solution from AMPS is shown in (b), with the neutral density in the meridional plane and the neutral temperature in the equatorial plane. Panel (c) is adapted fromKornbleuth et al (2020) and shows energetic neutral atom flux at 2.7 keV as viewed from near Earth and centered on the downwind (tail) direction in units of (cm 2 s sr keV) −1 . These synthetic maps produced from the neutral solution of AMPS can be directly compared to IBEX and IMAP missions to probe the global shape of the heliosphere.…”

Energetic pickup proton population downstream of the termination shock as revealed by the IBEX-Hi data

“…Therefore, our model takes into account the adiabatic heating due to the compression of decelerated plasma when it moves from the termination shock to the heliopause, as opposed to the models by Zirnstein et al (2017) and Kornbleuth et al (2020) where this process was neglected. Let us also explicitly emphasize that the solution (1) implies the neglect of the spatial diffusion, which is reasonable for energies of ∼few keVs (see Rucinski et al 1993;Chalov & Fahr 1997), and also the velocity diffusion.…”