Journal ArticleDOI
Structure of the turbulent interplanetary magnetic field
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TLDR
In this paper, the authors show that two widely used but apparently different models of the turbulent interplanetary magnetic field are closely related and that the anisotropy observed in the turbulence can be incorporated into both models by properly choosing the temporal and spatial dependence of the transverse velocity field at the solar source surface.Abstract:
We show that two widely used but apparently different models of the turbulent interplanetary magnetic field are closely related. One of these is the so-called quasi-static turbulence model, in which interplanetary magnetic field fluctuations are generated at a source surface near the Sun by random transverse plasma motions (such as supergranulation at the solar photosphere or perhaps reconnection) and are thereafter carried outward at a uniform constant speed in a radial solar wind. The other model of heliospheric magnetic turbulence is known as the two-component model, in which the random part of the field is decomposed into components along the field (slab fluctuations) and normal to it. Both models have provided us with useful simplified parameterizations of interplanetary fluctuations, and both enter into calculations that show good agreement with observations. Here we show that by properly choosing the temporal and spatial dependence of the transverse velocity field at the solar source surface in the quasi-static model, we can generate a two-component model (as well as many others). In particular, the anisotropy observed in the turbulence can be incorporated into both models. This study provides us with important insights that increase our understanding of turbulence and energetic particle transport in the heliosphere.read more
Citations
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Journal ArticleDOI
Self-consistent Coronal Heating and Solar Wind Acceleration from Anisotropic Magnetohydrodynamic Turbulence
TL;DR: In this article, a series of models for the plasma properties along open magnetic flux tubes rooted in solar coronal holes, streamers, and active regions are presented, which represent the first self-consistent solutions that combine chromospheric heating driven by an empirically guided acoustic wave spectrum; coronal heating from Alfven waves that have been partially reflected, then damped by anisotropic turbulent cascade; and solar wind acceleration from gradients of gas pressure, acoustic wave pressure, and Alfven wave pressure.
Journal ArticleDOI
Intermittency, nonlinear dynamics and dissipation in the solar wind and astrophysical plasmas.
William H. Matthaeus,William H. Matthaeus,William H. Matthaeus,Minping Wan,Sergio Servidio,Antonella Greco,Kareem Osman,Sean Oughton,Pablo Dmitruk +8 more
TL;DR: An overview is given of important properties of spatial and temporal intermittency, including evidence of its appearance in fluids, magnetofluids and plasmas, and its implications for understanding of heliospheric Plasmas.
Journal ArticleDOI
A fisk-parker hybrid heliospheric magnetic field with a solar-cycle dependence
TL;DR: In this paper, a refinement of the Fisk-Parker hybrid field was presented, which now includes a region bordering the solar rotational equator where magnetic field footpoint motion occurs only through diffusive reconnection.
Journal ArticleDOI
Cosmic Rays in the Inner Heliosphere: Insights from Observations, Theory and Models
TL;DR: 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.
Journal ArticleDOI
Density and Magnetic Field Signatures of Interplanetary 1/f Noise
William H. Matthaeus,William H. Matthaeus,B. Breech,Pablo Dmitruk,Alessandro Bemporad,Giannina Poletto,Marco Velli,Marco Romoli +7 more
TL;DR: In this article, the authors investigate the occurrence of 1/f noise in the interplanetary density and the magnetic field at varying heliocentric latitudes, and discuss possibilities that the 1 /f signal arises at varying altitudes, possibly surviving coronal dynamics.
References
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Journal ArticleDOI
Anisotropy in MHD turbulence due to a mean magnetic field
TL;DR: In this paper, the development of anisotropy in an initially isotropic spectrum is studied numerically for two-dimensional magnetohydrodynamic turbulence, due to the combined effects of an externally imposed dc magnetic field and viscous and resistive dissipation at high wave numbers.
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The Transport of Cosmic Rays across a Turbulent Magnetic Field
Joe Giacalone,J. R. Jokipii +1 more
TL;DR: In this article, the authors present a new analysis of the transport of cosmic rays in a turbulent magnetic field that varies in all three spatial dimensions using a numerical simulation that integrates the trajectories of an ensemble of test particles from which they obtain diffusion coefficients based on the particle motions.
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Evidence for the presence of quasi‐two‐dimensional nearly incompressible fluctuations in the solar wind
TL;DR: In this article, the authors proposed a model of the solar wind as a fluid which contains both classical transverse Alfvenic fluctuations and a population of quasi-transverse fluctuations.
Journal ArticleDOI
Proton and Electron Mean Free Paths: The Palmer Consensus Revisited
John W. Bieber,William H. Matthaeus,Charles W. Smith,W. Wanner,May-Britt Kallenrode,G. Wibberenz +5 more
TL;DR: In this paper, experimental and theoretical evidence suggests that the mean free path of cosmic-ray electrons and protons may be fundamentally different at low to intermediate (less than 50 MV) rigidities.
Journal ArticleDOI
Dominant two‐dimensional solar wind turbulence with implications for cosmic ray transport
TL;DR: In this article, two new methods for distinguishing two-dimensional (2D) turbulence from slab turbulence are applied to Helios magnetometer data, and they indicate that solar wind magnetic turbulence possesses a dominant (∼85 % by energy) 2D component.