Search Publications
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…
Turbulent Transport in a Three-dimensional Solar Wind
Bruno, R.; Zank, G. P.; Shiota, D. +3 more
Turbulence in the solar wind can play essential roles in the heating of coronal and solar wind plasma and the acceleration of the solar wind and energetic particles. Turbulence sources are not well understood and thought to be partly enhanced by interaction with the large-scale inhomogeneity of the solar wind and the interplanetary magnetic field …
Global Solar Magnetic Field Organization in the Outer Corona: Influence on the Solar Wind Speed and Mass Flux Over the Cycle
Réville, Victor; Brun, Allan Sacha
The dynamics of the solar wind depends intrinsically on the structure of the global solar magnetic field, which undergoes fundamental changes over the 11-year solar cycle. For instance, the wind terminal velocity is thought to be anti-correlated with the expansion factor, a measure of how the magnetic field varies with height in the solar corona, …
Modulation of Galactic Cosmic Rays in the Inner Heliosphere, Comparing with PAMELA Measurements
Qin, G.; Shen, Z. -N.
We develop a numerical model to study the time-dependent modulation of galactic cosmic rays in the inner heliosphere. In the model, a time-delayed modified Parker heliospheric magnetic field (HMF) and a new diffusion coefficient model, NLGCE-F, from Qin & Zhang, are adopted. In addition, the latitudinal dependence of magnetic turbulence magnit…
Theory and Transport of Nearly Incompressible Magnetohydrodynamics Turbulence. III. Evolution of Power Anistropy in Magnetic Field Fluctuations throughout the Heliosphere
Bruno, R.; Zank, G. P.; Shiota, D. +3 more
A theoretical model that describes the evolution of the power anisotropy in the energy-containing and inertial ranges throughout the heliosphere is developed for three possibilities: (i) no in situ sources of turbulence; (ii) stream-shear sources of 2D and slab turbulence; and (iii) a fully driven turbulence model that includes both stream-shear d…
New Evidence for Charge-sign-dependent Modulation During the Solar Minimum of 2006 to 2009
Potgieter, M. S.; Vos, E. E.; Munini, R. +1 more
The PAMELA space experiment, in orbit since 2006, has measured cosmic rays (CRs) through the most recent period of minimum solar activity with the magnetic field polarity as A < 0. During this entire time, galactic electrons and protons have been detected down to 70 MV and 400 MV, respectively, and their differential variation in intensity with…
High-latitude Conic Current Sheets in the Solar Wind
Tokumaru, Munetoshi; Fujiki, Ken'ichi; Malova, Helmi V. +7 more
We provide observational evidence for the existence of large-scale cylindrical (or conic-like) current sheets (CCSs) at high heliolatitudes. Long-lived CCSs were detected by Ulysses during its passages over the South Solar Pole in 1994 and 2007. The characteristic scale of these tornado-like structures is several times less than a typical width of…
Reconnection-driven Magnetohydrodynamic Turbulence in a Simulated Coronal-hole Jet
DeVore, C. Richard; Karpen, Judith T.; Uritsky, Vadim M. +1 more
Extreme-ultraviolet and X-ray jets occur frequently in magnetically open coronal holes on the Sun, especially at high solar latitudes. Some of these jets are observed by white-light coronagraphs as they propagate through the outer corona toward the inner heliosphere, and it has been proposed that they give rise to microstreams and torsional Alfvén…
Evolution of Alfvénic Fluctuations inside an Interplanetary Coronal Mass Ejection and Their Contribution to Local Plasma Heating: Joint Observations from 1.0 to 5.4 au
Li, Hui; Wang, Chi; Richardson, John D. +1 more
Tracking an interplanetary coronal mass ejection (ICME) by widely separated spacecraft could provide us with a good opportunity to study the evolution of embedded Alfvénic fluctuations (AFs) and their possible contribution to local plasma heating directly. In this study, an ICME observed by Wind at 1.0 au on 1998 March 4-6 is tracked to the locati…
A Ulysses Detection of Secondary Helium Neutrals
Wood, Brian E.; Müller, Hans-Reinhard; Witte, Manfred
The Interstellar Boundary EXplorer (IBEX) mission has recently studied the flow of interstellar neutral He atoms through the solar system and discovered the existence of a secondary He flow that likely originates in the outer heliosheath. We find evidence for this secondary component in Ulysses data. By coadding hundreds of Ulysses He beam maps to…