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The Solar Wind as a Turbulence Laboratory

Bruno, Roberto; Carbone, Vincenzo

In this review we will focus on a topic of fundamental importance for both astrophysics and plasma physics, namely the occurrence of large-amplitude low-frequency fluctuations of the fields that describe the plasma state. This subject will be treated within the context of the expanding solar wind and the most meaningful advances in this research f…

Heliolatitude and Time Variations of Solar Wind Structure from in situ Measurements and Interplanetary Scintillation Observations

McComas, D. J.; Bzowski, M.; Tokumaru, M. +2 more

The 3D structure of the solar wind and its evolution in time are needed for heliospheric modeling and interpretation of energetic neutral atoms observations. We present a model to retrieve the solar wind structure in heliolatitude and time using all available and complementary data sources. We determine the heliolatitude structure of solar wind sp…

Three-dimensional Features of the Outer Heliosphere due to Coupling between the Interstellar and Interplanetary Magnetic Fields. IV. Solar Cycle Model Based on Ulysses Observations

McComas, D. J.; Pogorelov, N. V.; Zank, G. P. +3 more

The solar cycle has a profound influence on the solar wind (SW) interaction with the local interstellar medium (LISM) on more than one timescales. Also, there are substantial differences in individual solar cycle lengths and SW behavior within them. The presence of a slow SW belt, with a variable latitudinal extent changing within each solar cycle…

A Global Wave-driven Magnetohydrodynamic Solar Model with a Unified Treatment of Open and Closed Magnetic Field Topologies

Gombosi, T. I.; Landi, E.; Jin, M. +3 more

We describe, analyze, and validate the recently developed Alfvén Wave Solar Model, a three-dimensional global model starting from the top of the chromosphere and extending into interplanetary space (out to 1-2 AU). This model solves the extended, two-temperature magnetohydrodynamics equations coupled to a wave kinetic equation for low-frequency Al…

Signatures of kinetic instabilities in the solar wind

Landi, Simone; Hellinger, Petr; Velli, Marco +3 more

An analysis of ion non-thermal properties in the fast solar wind based on Ulysses data is reported. The radial evolution of the main proton moments (density, temperature, and drift velocities) and their empirical correlations with other plasma parameters are investigated in detail and compared with theoretical expectations. The stability of the pl…

An improved model for the infrared emission from the zodiacal dust cloud: cometary, asteroidal and interstellar dust

Rowan-Robinson, M.; May, B.

We model the infrared emission from zodiacal dust detected by the IRAS and COBE missions, with the aim of estimating the relative contributions of asteroidal, cometary and interstellar dust to the zodiacal cloud. Our most important result is the detection of an isotropic component of foreground radiation due to the interstellar dust.

The dust…

An Ab Initio Model for Cosmic-ray Modulation

Burger, R. A.; Engelbrecht, N. E.

A proper understanding of the effects of turbulence on the diffusion and drift of cosmic rays (CRs) is of vital importance for a better understanding of CR modulation in the heliosphere. This study presents an ab initio model for CR modulation, incorporating for the first time the results yielded by a two-component turbulence transport model. This…

Decades-Long Changes of the Interstellar Wind Through Our Solar System

McComas, D. J.; Frisch, P. C.; Schwadron, N. A. +8 more

The journey of the Sun through the dynamically active local interstellar medium creates an evolving heliosphere environment. This motion drives a wind of interstellar material through the heliosphere that has been measured with Earth-orbiting and interplanetary spacecraft for 40 years. Recent results obtained by NASA's Interstellar Boundary Explor…

Cosmic Rays in the Inner Heliosphere: Insights from Observations, Theory and Models

Potgieter, M. S.

The global modulation of galactic cosmic rays in the inner heliosphere is determined by four major mechanisms: convection, diffusion, particle drifts (gradient, curvature and current sheet drifts), and adiabatic energy losses. When these processes combine to produce modulation, the complexity increases significantly especially when one wants to de…

Solar Drivers of 11-yr and Long-Term Cosmic Ray Modulation

Richardson, I. G.; Ling, A. G.; Cliver, E. W.

In the current paradigm for the modulation of galactic cosmic rays (GCRs), diffusion is taken to be the dominant process during solar maxima while drift dominates at minima. Observations during the recent solar minimum challenge the pre-eminence of drift at such times. In 2009, the ∼2 GV GCR intensity measured by the Newark neutron monitor increas…