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Science Opportunities for IMAP-Lo Observations of Interstellar Neutral Hydrogen and Deuterium during a Maximum of Solar Activity
Möbius, E.; Schwadron, N. A.; Bzowski, M. +1 more
Direct-sampling observations of interstellar neutral gas, including hydrogen and deuterium, have been performed for more than one cycle of solar activity by IBEX. The IBEX viewing is restricted to directions perpendicular to the spacecraft–Sun line, which limits the observations to several months each year. This restriction is removed in the forth…
A Comprehensive Comparison of Various Galactic Cosmic-Ray Models to the State-of-the-art Particle and Radiation Measurements
Guo, Jingnan; Liu, Weihao; Wang, Yubao +1 more
Galactic cosmic rays (GCRs) are the slowly varying background energetic particles that originate outside the solar system, are modulated by the heliospheric magnetic field, and pose ongoing radiation hazards to deep space exploration missions. To assess the potential radiation risk, various models have been developed to predict the GCR flux near E…
On the General Correlation between 3D Solar Wind Speed and Density Model and Solar Proxies
Bzowski, M.; Tokumaru, M.; Porowski, C.
The solar wind (SW) is a supersonic outflow of plasma from the solar corona, with the latitudinal speed and density profiles varying with the solar activity. The SW protons charge exchange with the inflowing interstellar neutral atoms and create energetic neutral atoms (ENAs), which bring information on the physical state of the plasma within the …
The GALPROP Cosmic-ray Propagation and Nonthermal Emissions Framework: Release v57
Jóhannesson, G.; Moskalenko, I. V.; Porter, T. A.
The past decade has brought impressive advances in the astrophysics of cosmic rays (CRs) and multiwavelength astronomy, thanks to the new instrumentation launched into space and built on the ground. Modern technologies employed by those instruments provide measurements with unmatched precision, enabling searches for subtle signatures of dark matte…
Very Local Interstellar Medium Revealed by a Complete Solar Cycle of Interstellar Neutral Helium Observations with IBEX
McComas, D. J.; Fuselier, S. A.; Galli, A. +8 more
The IBEX-Lo instrument on board the Interstellar Boundary Explorer (IBEX) mission samples interstellar neutral (ISN) helium atoms penetrating the heliosphere from the very local interstellar medium (VLISM). In this study, we analyze the IBEX-Lo ISN helium observations covering a complete solar cycle, from 2009 through 2020 using a comprehensive un…
A New 3D Solar Wind Speed and Density Model Based on Interplanetary Scintillation
Bzowski, M.; Tokumaru, M.; Porowski, C.
The solar wind (SW) is an outflow of the solar coronal plasma, which expands supersonically throughout the heliosphere. SW particles interact by charge exchange with interstellar neutral atoms; on the one hand, they modify the distribution of this gas in interplanetary space, and, on the other hand, they are the seed populations for heliospheric p…
Interstellar Neutral He Parameters from Crossing Parameter Tubes with the Interstellar Mapping and Acceleration Probe Informed by 10 yr of Interstellar Boundary Explorer Observations
McComas, D. J.; Fuselier, S. A.; Möbius, E. +11 more
The Sun's motion through the interstellar medium leads to an interstellar neutral (ISN) wind through the heliosphere. Several ISN species, including He, moderately depleted by ionization are observed with pickup ions and directly imaged. Since 2009, analyzed Interstellar Boundary Explorer (IBEX) observations returned a precise 4D parameter tube as…
Whence the Interstellar Magnetic Field Shaping the Heliosphere?
McComas, D. J.; Redfield, Seth; Frisch, P. C. +15 more
Measurements of starlight polarized by aligned interstellar dust grains are used to probe the relation between the orientation of the ambient interstellar magnetic field (ISMF) and the ISMF traced by the ribbons of energetic neutral atoms discovered by the Interstellar Boundary Explorer spacecraft. We utilize polarization data, many acquired speci…
Heliosheath Proton Distribution in the Plasma Reference Frame
McComas, D. J.; Dayeh, M. A.; Swaczyna, P. +2 more
Properties of the inner heliosheath (IHS) plasma are inferred from energetic neutral atom (ENA) observations by ∼1 au spacecraft. However, the Compton-Getting effect due to the plasma velocity relative to the spacecraft is rarely taken into account, even though the plasma speed is a significant fraction of the ENA speed. In this study, we transfor…
Numerical Modeling of Latitudinal Gradients for Galactic Cosmic-Ray Protons during Solar Minima: Comparing with Ulysses Observations
Qin, Gang; Shen, Zhenning; Zuo, Pingbing +2 more
The latitudinal gradients of galactic cosmic-ray (GCR) protons measured by Ulysses during two successive minima provide a unique opportunity to study the modulation effects in polar regions of the heliosphere. In this work, a GCR modulation model based on numerically solving the Parker transport equation is used to study the latitudinal distributi…