Voyager 2 observations throughout the heliosheath from the termination shock to the heliopause are used to normalize and constrain model pickup ion (PUI) fluxes. Integrating normalized PUI fluxes along the Voyager 2 trajectory through the heliosheath, and combining these integral fluxes with the energy-dependent charge-exchange cross section and the neutral hydrogen density, produces semi-empirical estimates of the energetic neutral atom (ENA) fluxes from the heliosheath. These estimated ENA fluxes are compared with observed ENA fluxes from the Interstellar Boundary Explorer (IBEX) to determine what percentage of the observed fluxes at each IBEX energy are from the heliosheath. These percentages are a maximum of ∼10% for most energies and depend strongly on termination shock properties, plasma density, bulk plasma flow characteristics, the shape of the heliopause, and turbulent energy diffusion in the heliosheath.

As the supersonic solar wind (SW) approaches Earth's magnetosphere, it encounters the bow shock (BS), which heats and decelerates the incoming plasma. Earth's BS is classified as a supercritical collisionless shock, which means that additional heating mechanisms beyond magnetohydrodynamics resistivity are required to account for the amount of heating that takes place across the shock. Shock reflection is considered to be a significant mechanism capable of providing this extra level of heating (Gosling & Robson, 1985). Heating via shock reflection occurs when an incident ion reflects off of the shock and gyrates through the upstream region, gaining energy in the upstream transverse electric field (Sonnerup, 1969). The ion then returns to the shock with a considerable energy gain and is transmitted into the downstream region. The relative amount of heating via shock reflection depends on the shock strength and the angle ( 𝐴𝐴 𝜽𝜽𝑩𝑩𝑩𝑩 ) between the upstream magnetic field and shock normal (Gosling & Robson, 1985). For quasi-perpendicular geometries ( 𝐴𝐴 𝜽𝜽𝑩𝑩𝑩𝑩 > 𝟒𝟒𝟒𝟒 • ), up to ∼20% of incident SW protons reflect off of the shock (Paschmann & Sckopke, 1983). Once downstream, these protons form a filled shell distribution with radius in velocity space ∼V SW , superimposed on the heated core SW population (Gosling & Robson, 1985). For quasi-parallel shock geometries ( 𝐴𝐴 𝜽𝜽𝑩𝑩𝑩𝑩 < 𝟒𝟒𝟒𝟒 • ) , a smaller fraction of protons undergoes specular reflection, and other mechanisms such as wave activity are expected contribute to the heating process (Gosling & Robson, 1985). At the subsolar portion of the magnetopause, the plasma is nearly stationary and the majority of the bulk flow energy in the SW has gone into plasma heating. This results in a hot and dense multi-component population of shocked protons in the upstream magnetosheath.

This paper describes a novel approach to emulate a universal quantum computer with a wholly classical system, one that uses a signal of bounded duration and amplitude to represent an arbitrary quantum state. The signal may be of any modality (e.g. acoustic, electromagnetic, etc.) but this paper will focus on electronic signals. Individual qubits are represented by in-phase and quadrature sinusoidal signals, while unitary gate operations are performed using simple analog electronic circuit devices. In this manner, the Hilbert space structure of a multi-qubit quantum state, as well as a universal set of gate operations, may be fully emulated classically. Results from a programmable prototype system are presented and discussed.

An extended interval of perturbed magnetospheric conditions in November 2016 supported increased convection and sunward transport of plasmaspheric material. During this period of time the Magnetospheric Multiscale satellites, with their apogees along Earth's dusk‐side outer magnetosphere, encountered several cold plasma density structures at the same time as plasma bulk flows capable of accelerating hidden cold plasma occurred. Investigating the charged particle and fields data during two subintervals showed that the satellites made direct measurements of cold plasmaspheric ions embedded within multicomponent hot plasmas as well as electromagnetic emissions consistent with electromagnetic ion cyclotron (EMIC) waves. The complex in situ ion composition measurements were applied to linear wave modeling to interpret the impacts of cold and hot ion species on wave growth and band structure. Although the waves for both intervals were predicted to have peak growth rate below ΩHe+, substantial differences were observed among all other dispersive properties. The modeling also showed EMIC waves generated in the presence of heavy ions had growth rates and unstable wave numbers always smaller than predicted for a pure proton‐electron plasma. The results provide implications for future investigation of EMIC wave generation with and without direct measurements of the cold and hot plasma composition as well as of subsequent wave‐particle interactions.