Search Publications
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…
Theory of Cosmic Ray Transport in the Heliosphere
Rankin, J. S.; Potgieter, M. S.; Ruffolo, D. +6 more
Modelling the transport of cosmic rays (CRs) in the heliosphere represents a global challenge in the field of heliophysics, in that such a study, if it were to be performed from first principles, requires the careful modelling of both large scale heliospheric plasma quantities (such as the global structure of the heliosphere, or the heliospheric m…
The Structure of the Large-Scale Heliosphere as Seen by Current Models
Heerikhuisen, Jacob; Fraternale, Federico; Pogorelov, Nikolai +6 more
This review summarizes the current state of research aiming at a description of the global heliosphere using both analytical and numerical modeling efforts, particularly in view of the overall plasma/neutral flow and magnetic field structure, and its relation to energetic neutral atoms. Being part of a larger volume on current heliospheric researc…
Alpha-Proton Differential Flow of the Young Solar Wind: Parker Solar Probe Observations
Bale, S. D.; Allen, R. C.; Raouafi, N. E. +5 more
The velocity of alpha particles relative to protons can vary depending on the solar wind type and distance from the Sun. Measurements from the previous spacecraft provided the alpha-proton differential velocities down to 0.3 au. The Parker Solar Probe (PSP) now enables insights into differential flows of the newly accelerated solar wind closer to …
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…
Anomalous Cosmic Rays and Heliospheric Energetic Particles
Fichtner, H.; Leske, R. A.; Hill, M. E. +7 more
We present a review of Anomalous Cosmic Rays (ACRs), including the history of their discovery and recent insights into their acceleration and transport in the heliosphere. We focus on a few selected topics including a discussion of mechanisms of their acceleration, escape from the heliosphere, their effects on the dynamics of the heliosheath, tran…
Recent Developments in Particle Acceleration at Shocks: Theory and Observations
Giacalone, Joe; Perri, Silvia; Fichtner, Horst +2 more
Energetic particles represent an important component of the plasma in the heliosphere. They range from particles accelerated at impulsive events in the solar corona and at large scale structures in the interplanetary medium, to anomalous cosmic rays accelerated at the boundaries of the heliosphere. In-situ satellite observations, numerical simulat…
Turbulence in the Outer Heliosphere
Zank, Gary P.; Adhikari, Laxman; Zhao, Lingling +9 more
The solar wind (SW) and local interstellar medium (LISM) are turbulent media. Their interaction is governed by complex physical processes and creates heliospheric regions with significantly different properties in terms of particle populations, bulk flow and turbulence. Our knowledge of the solar wind turbulence nature and dynamics mostly relies o…
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…
Mixing Interstellar Clouds Surrounding the Sun
Zank, Gary P.; Redfield, Seth; Winslow, Réka M. +9 more
On its journey through the Galaxy, the Sun passes through diverse regions of the interstellar medium. High-resolution spectroscopic measurements of interstellar absorption lines in spectra of nearby stars show absorption components from more than a dozen warm partially ionized clouds within 15 pc of the Sun. The two nearest clouds-the Local Inters…