Search Publications
Solar wind stream interaction regions throughout the heliosphere
Richardson, Ian G.
This paper focuses on the interactions between the fast solar wind from coronal holes and the intervening slower solar wind, leading to the creation of stream interaction regions that corotate with the Sun and may persist for many solar rotations. Stream interaction regions have been observed near 1 AU, in the inner heliosphere (at
The Steady Global Corona and Solar Wind: A Three-dimensional MHD Simulation with Turbulence Transport and Heating
Matthaeus, William H.; Goldstein, Melvyn L.; Usmanov, Arcadi V. +1 more
We present a fully three-dimensional magnetohydrodynamic model of the solar corona and solar wind with turbulence transport and heating. The model is based on Reynolds-averaged solar wind equations coupled with transport equations for turbulence energy, cross helicity, and correlation scale. The model includes separate energy equations for protons…
An Unusual Energetic Particle Flux Enhancement Associated with Solar Wind Magnetic Island Dynamics
Chen, Y.; Zank, G. P.; Zhao, L. -L. +4 more
The possibility that charged particles are accelerated statistically in a “sea” of small-scale interacting magnetic flux ropes in the supersonic solar wind is gaining credence. In this Letter, we extend the Zank et al. statistical transport theory for a nearly isotopic particle distribution by including an escape term corresponding to particle los…
On the 1/f Spectrum in the Solar Wind and Its Connection with Magnetic Compressibility
Matteini, L.; Horbury, T. S.; Chen, C. H. K. +1 more
We discuss properties of Alfvénic fluctuations with large amplitude in plasmas characterized by low magnetic field compression. We note that in such systems power laws cannot develop with arbitrarily steep slopes at large scales, i.e., when | δ {\boldsymbol{B}}| becomes of the order of the background field | {\boldsymbol{B}}| . In such systems the…
Propagation of cosmic rays in heliosphere: The HELMOD model
Gervasi, M.; Rancoita, P. G.; Boschini, M. J. +2 more
The heliospheric modulation model HELMOD is a two dimensional treatment dealing with the helio-colatitude and radial distance from Sun and is employed to solve the transport-equation for the GCR propagation through the heliosphere down to Earth. This work presents the current version 3 of the HELMOD model and reviews how main processes involved in…
Abundances, Ionization States, Temperatures, and FIP in Solar Energetic Particles
Reames, Donald V.
The relative abundances of chemical elements and isotopes have been our most effective tool in identifying and understanding the physical processes that control populations of energetic particles. The early surprise in solar energetic particles (SEPs) was 1000-fold enhancements in {}3He/{}4He from resonant wave-particle inter…
HelMod in the Works: From Direct Observations to the Local Interstellar Spectrum of Cosmic-Ray Electrons
Jóhannesson, G.; Moskalenko, I. V.; Porter, T. A. +11 more
The local interstellar spectrum (LIS) of cosmic-ray (CR) electrons for the energy range 1 MeV to 1 TeV is derived using the most recent experimental results combined with the state-of-the-art models for CR propagation in the Galaxy and in the heliosphere. Two propagation packages, GALPROP and HELMOD, are combined to provide a single framework that…
Geoeffectiveness of interplanetary shocks controlled by impact angles: A review
Samsonov, A. A.; Oliveira, D. M.
The high variability of the Sun's magnetic field is responsible for the generation of perturbations that propagate throughout the heliosphere. Such disturbances often drive interplanetary shocks in front of their leading regions. Strong shocks transfer momentum and energy into the solar wind ahead of them which in turn enhance the solar wind inter…
Kinetic Theory and Fast Wind Observations of the Electron Strahl
Wilson, Lynn B., III; Horaites, Konstantinos; Viñas, Adolfo F. +2 more
We develop a model for the strahl population in the solar wind - a narrow, low-density and high-energy electron beam centred on the magnetic field direction. Our model is based on the solution of the electron drift-kinetic equation at heliospheric distances where the plasma density, temperature and the magnetic field strength decline as power laws…
Modulation of Galactic Cosmic Rays in the Inner Heliosphere over Solar Cycles
Qin, G.; Shen, Z. -N.
The 11- and 22-year modulation of galactic cosmic rays (GCRs) in the inner heliosphere is studied using a numerical model developed by Qin and Shen in 2017. Based on the numerical solutions of Parker’s transport equations, the model incorporates a modified Parker heliospheric magnetic field, a locally static time-delayed heliosphere, and a time-de…