Search Publications
The Physical Processes of CME/ICME Evolution
Vršnak, Bojan; Lugaz, Noé; Liu, Ying D. +4 more
As observed in Thomson-scattered white light, coronal mass ejections (CMEs) are manifest as large-scale expulsions of plasma magnetically driven from the corona in the most energetic eruptions from the Sun. It remains a tantalizing mystery as to how these erupting magnetic fields evolve to form the complex structures we observe in the solar wind a…
Possible Dark Matter Annihilation Signal in the AMS-02 Antiproton Data
Yuan, Qiang; Fan, Yi-Zhong; Tsai, Yue-Lin Sming +1 more
Using the latest AMS-02 cosmic-ray antiproton flux data, we search for a potential dark matter annihilation signal. The background parameters about the propagation, source injection, and solar modulation are not assumed a priori but based on the results inferred from the recent B / C ratio and proton data measurements instead. The possible dark ma…
Geoeffective Properties of Solar Transients and Stream Interaction Regions
Balogh, A.; Kilpua, E. K. J.; von Steiger, R. +1 more
Interplanetary Coronal Mass Ejections (ICMEs), their possible shocks and sheaths, and co-rotating interaction regions (CIRs) are the primary large-scale heliospheric structures driving geospace disturbances at the Earth. CIRs are followed by a faster stream where Alfvénic fluctuations may drive prolonged high-latitude activity. In this paper we hi…
Origins of the Ambient Solar Wind: Implications for Space Weather
Cranmer, Steven R.; Riley, Pete; Gibson, Sarah E.
The Sun's outer atmosphere is heated to temperatures of millions of degrees, and solar plasma flows out into interplanetary space at supersonic speeds. This paper reviews our current understanding of these interrelated problems: coronal heating and the acceleration of the ambient solar wind. We also discuss where the community stands in its abilit…
Acceleration and Propagation of Solar Energetic Particles
Klein, Karl-Ludwig; Dalla, Silvia
Solar Energetic Particles (SEPs) are an important component of Space Weather, including radiation hazard to humans and electronic equipment, and the ionisation of the Earth's atmosphere. We review the key observations of SEPs, our current understanding of their acceleration and transport, and discuss how this knowledge is incorporated within Space…
Solution of Heliospheric Propagation: Unveiling the Local Interstellar Spectra of Cosmic-ray Species
Orlando, E.; Jóhannesson, G.; Moskalenko, I. V. +14 more
Local interstellar spectra (LIS) for protons, helium, and antiprotons are built using the most recent experimental results combined with state-of-the-art models for propagation in the Galaxy and heliosphere. Two propagation packages, GALPROP and HelMod, are combined to provide a single framework that is run to reproduce direct measurements of cosm…
Propagation of cosmic rays in the AMS-02 era
Fang, Kun; Yuan, Qiang; Lin, Su-Jie +1 more
In this work we use the newly reported boron-to-carbon ratio (B/C) from AMS-02 and the time-dependent proton fluxes from PAMELA and AMS-02 to constrain the source and propagation parameters of cosmic rays in the Milky Way. A linear correlation of the solar modulation parameter with solar activities is assumed to account for the time-varying cosmic…
Modeling observations of solar coronal mass ejections with heliospheric imagers verified with the Heliophysics System Observatory
Rodriguez, L.; Zhang, T. L.; Möstl, C. +19 more
We present an advance toward accurately predicting the arrivals of coronal mass ejections (CMEs) at the terrestrial planets, including Earth. For the first time, we are able to assess a CME prediction model using data over two thirds of a solar cycle of observations with the Heliophysics System Observatory. We validate modeling results of 1337 CME…
Interstellar Pickup Ion Observations to 38 au
McComas, D. J.; Schwadron, N. A.; Szalay, J. R. +9 more
We provide the first direct observations of interstellar H+ and He+ pickup ions in the solar wind from 22 to 38 au. We use the Vasyliunas and Siscoe model functional form to quantify the pickup ion distributions, and while the fit parameters generally lie outside their physically expected ranges, this form allows fits that qu…
Origin of small-scale anisotropies in Galactic cosmic rays
Mertsch, Philipp; Ahlers, Markus
The arrival directions of Galactic cosmic rays are highly isotropic. This is expected from the presence of turbulent magnetic fields in our Galactic environment that repeatedly scatter charged cosmic rays during propagation. However, various cosmic ray observatories have identified weak anisotropies of various angular sizes and with relative inten…