Compound and Perpendicular Diffusion of Cosmic Rays and Random Walk of the Field Lines. I. Parallel Particle Transport Models

Webb, G. M.; Zank, G. P.; Kaghashvili, E. Kh.; Roux, J. A. le

doi:10.1086/507415

Cited by 125 publications

(115 citation statements)

References 62 publications

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“…Equation (4) can also be obtained from the ChapmanKolmogorov equation (see, e.g., Webb et al 2006), which has the form…”

Section: Generalized Compound Diffusion Of Charged Particlesmentioning

confidence: 99%

“…Although this problem has been discussed in several papers (e.g. Jokipii 1966;Bieber & Matthaeus 1997;Kóta & Jokipii 2000;Matthaeus et al 2003;Shalchi et al 2004;Webb et al 2006;Shalchi 2006), a final solution has not been provided so far. The perpendicular transport of charged particles is a central problem in astrophysics, since the knowledge of the diffusion tensor for particle transport parallel and perpendicular to the prescribed external magnetic field is essential for describing solar energetic particles (Dröge 2000), the modulation of Galactic cosmic rays (Burger & Hattingh 1998), diffusive shock acceleration, and the lifetime of cosmic rays in the Galaxy (Jokipii & Parker 1969).…”

Section: Introductionmentioning

confidence: 99%

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A new theory for perpendicular transport of cosmic rays

Shalchi¹,

Kourakis²

2007

A&A

103

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We present an improved nonlinear theory for the perpendicular transport of charged particles. This approach is based on an improved nonlinear treatment of field-line random walk in combination with a generalized compound diffusion model. The generalized compound diffusion model employed is more systematic and reliable, in comparison with previous theories. Furthermore, the theory shows remarkably good agreement with test-particle simulations and solar wind observations.

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“…Equation (4) can also be obtained from the ChapmanKolmogorov equation (see, e.g., Webb et al 2006), which has the form…”

Section: Generalized Compound Diffusion Of Charged Particlesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A new theory for perpendicular transport of cosmic rays

Shalchi¹,

Kourakis²

2007

A&A

103

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“…The perpendicular subdiffusion is a result of particles tracing back the field lines after pitch angle diffusion, and is related to the so-called compound diffusion (Kóta and Jokipii 2000;Webb et al 2006) discussed in Sect. 2.4.…”

Section: Test Particle Simulations Of Transport In the Presence Of Mamentioning

confidence: 99%

Nonclassical Transport and Particle-Field Coupling: from Laboratory Plasmas to the Solar Wind

Perrone

Dendy

Furno

et al. 2013

Space Sciences Series of ISSI

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Understanding transport of thermal and suprathermal particles is a fundamental issue in laboratory, solar-terrestrial, and astrophysical plasmas. For laboratory fusion experiments, confinement of particles and energy is essential for sustaining the plasma long enough to reach burning conditions. For solar wind and magnetospheric plasmas, transport properties determine the spatial and temporal distribution of energetic particles, which can be harmful for spacecraft functioning, as well as the entry of solar wind plasma into the magnetosphere. For astrophysical plasmas, transport properties determine the efficiency of particle acceleration processes and affect observable radiative signatures. In all cases, transport depends on the interaction of thermal and suprathermal particles with the electric and magnetic fluctuations in the plasma. Understanding transport therefore requires us to understand these interactions, which encompass a wide range of scales, from magnetohydrodynamic to kinetic scales, with larger scale structures also having a role. The wealth of transport studies during recent decades has shown the existence of a variety of regimes that differ from the classical quasilinear regime. In this paper we give an overview of nonclassical plasma transport regimes, discussing theoretical approaches to superdiffusive and subdiffusive transport, wave-particle interactions at microscopic kinetic scales, the influence of coherent structures and of avalanching transport, and the results of numerical simulations and experimental data analyses. Applications to laboratory plasmas and space plasmas are discussed.

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“…Discussing magnetic field line random walk (FLRW) in two or three dimensions (e.g., Jokipii & Parker 1969;see also Isichenko 1992;Bakunin 2010, for an introduction) is important in the astrophysical context because field line displacement can be used as an intermediate step to investigate particle scattering (Matthaeus et al 2003;Shalchi & Kourakis 2007b;Tautz et al 2008) via the compound diffusion approach (e.g., Kóta & Jokipii 2000;Webb et al 2006). For FLRW, several analytical theories have been proposed to describe the random walk of stochastic magnetic field lines (Matthaeus et al 1995;Zimbardo et al 2000;Ruffolo et al 2006;Shalchi & Kourakis 2007a;Shalchi & Weinhorst 2009;Shalchi & Qin 2010).…”

Section: Introductionmentioning

confidence: 99%

The role of magnetic helicity for field line diffusion and drift

Tautz

Lerche

2011

A&A

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Aims. This paper discusses the systematic drift of magnetic field lines under the influence of asymmetric turbulence where the asymmetry is caused by Alfvén wave helicity. Methods. The basic method of investigation is numerically tracing random magnetic field lines to discuss the average displacement of field lines owing to the asymmetric turbulence. Results. The main result is that as long as one has any non-zero degree of asymmetric turbulence, there is a systematic drift of field lines on average; an effect not seen when the turbulence is taken to be symmetric. This result implies that diffusion of field lines takes place relative to the mean drift and so alters the consequences for discussions of field line diffusion.

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Compound and Perpendicular Diffusion of Cosmic Rays and Random Walk of the Field Lines. I. Parallel Particle Transport Models

Cited by 125 publications

References 62 publications

A new theory for perpendicular transport of cosmic rays

A new theory for perpendicular transport of cosmic rays

Nonclassical Transport and Particle-Field Coupling: from Laboratory Plasmas to the Solar Wind

The role of magnetic helicity for field line diffusion and drift

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