The Effect of Wave-Particle Interactions on the Propagation of Cosmic Rays

Kulsrud, Russell M.; Pearce, William P.

doi:10.1086/149981

Cited by 806 publications

(820 citation statements)

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“…(Here "fast" is defined from Jokipii (1966) where the ratio of electric to magnetic forces on the particles in the interplanetary field is Fe/FB ' VAlfven/BC << 1). These include Jokipii (1966Jokipii ( , 1968bJokipii ( , 1971, Roelof (1966), Hasselmann and Wibberenz (1968), and Kulsrud and Pearce (1969). All procede from a Fokker-Planck equation to describe the diffusion in pitch angle and position.…”

Section: L2 Basic Elements Of Cosmic Ray Modulationmentioning

confidence: 99%

Modulation of low-energy cosmic rays

Sari¹

1975

J. Geophys. Res.

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Recent theories have related the diffusion of cosmic rays in the solar wind to the power spectrum of interplanetary magnetic field fluctuations. In this study the power spectrum‐diffusion coefficient relation for low‐energy protons (T < 80 MeV) is tested directly, and the relative contribution to the scattering from directional discontinuities in the magnetic field is examined. Modulation parameters Vw/Krr, the solar wind speed divided by the radial diffusion coefficient, are calculated from Pioneer 6 magnetic field and solar wind data and are compared with simultaneous Imp 3 observations of the 20‐ to 80‐MeV proton flux. Daily variations in the 40‐ to 80‐MeV proton flux are found to respond to changes in Vw/Krr, as is predicted by a perturbation solution of the Fokker‐Planck equation once the contribution from directional discontinuities in the magnetic field is subtracted from the diffusion coefficients. This finding is interpreted to imply that a large percentage of the identified discontinuities are basically tangential. A lack of correlation between the 20‐ to 40‐MeV flux and the parameter changes is interpreted as being due to either the invalidity of the theory at lower energies or the presence of a continuous flux of high‐energy solar protons. A well‐defined time lag between changes in the 60‐ to 80‐MeV proton flux and corresponding changes in Vw/Krr is observed during a period when the interplanetary magnetic field is predominantly radial and the Imp 3‐sun‐Pioneer 6 angle is greater than 10°. This lag is consistent with the interpretation of little or no cross‐field diffusion or a perpendicular diffusion coefficient less than 3 × 1019 cm²/s.

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Section: L2 Basic Elements Of Cosmic Ray Modulationmentioning

confidence: 99%

Modulation of low-energy cosmic rays

Sari¹

1975

J. Geophys. Res.

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“…Note that the numerical coefficient in the last expression may vary depending on the average ion and neutral masses and can be higher by a factor of a few (Kulsrud and Pearce 1969;Nakano 1984) than the estimate in eq. (27) suggests.…”

Section: Break Momentummentioning

confidence: 91%

Collisionless Shocks in Partly Ionized Plasma with Cosmic Rays: Microphysics of Non-thermal Components

Bykov

Malkov

Raymond

et al. 2013

Microphysics of Cosmic Plasmas

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In this review we discuss some observational aspects and theoretical models of astrophysical collisionless shocks in partly ionized plasma with the presence of nonthermal components. A specific feature of fast strong collisionless shocks is their ability to accelerate energetic particles that can modify the shock upstream flow and form the shock precursors. We discuss the effects of energetic particle acceleration and associated magnetic field amplification and decay in the extended shock precursors on the line and continuum multi-wavelength emission spectra of the shocks. Both Balmer-type and radiative astrophysical shocks are discussed in connection to supernova remnants interacting with partially neutral clouds. Quantitative models described in the review predict a number of observable line-like emission features that can be used to reveal the physical state of the matter in the shock precursors and the character of nonthermal processes in the shocks. Implications of recent progress of gamma-ray observations of supernova remnants in molecular clouds are highlighted.

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“…The drag imparted in this manner by a collision between ion and neutral also causes ambipolar diffusion, a mechanism used to describe the Alfvén wave damping by cosmic rays (Kulsrud & Pearce 1969) and also discussed by Oishi & Mac Low (2006) in the context of molecular clouds.…”

Section: Introductionmentioning

confidence: 92%

“…In the context of partially ionized space and astrophysical plasmas, these waves interact with the neutral gas and govern numerous properties. For instance, Kulsrud & Pearce (1969) noted that the interaction of a neutral gas and plasma can damp Alfvén waves. Neutrals interacting with plasma via a relative drag process results in ambipolar diffusion.…”

Section: Introductionmentioning

confidence: 99%

Dynamics of Alfvén waves in partially ionized astrophysical plasmas

Shaikh

2009

J. Plasma Phys.

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Abstract. We develop a two dimensional, self-consistent, compressible fluid model to study evolution of Alfvenic modes in partially ionized astrophysical and space plasmas. The partially ionized plasma consists mainly of electrons, ions and significant neutral atoms. The nonlinear interactions amongst these species take place predominantly through direct collision or charge exchange processes. Our model uniquely describe the interaction processes between two distinctly evolving fluids. In our model, the electrons and ions are described by a single fluid compressible magnetohydrodynamic (MHD) model and are coupled self-consistently to the neutral fluid via compressible hydrodynamic equations. Both plasma and neutral fluids are treated with different energy equations that adequately enable us to monitor non adiabatic and thermal energy exchange processes between these two distinct fluids. Based on our self-consistent model, we find that the propagation speed of Alfvenic modes in space and astrophysical plasma is slowed down because these waves are damped predominantly due to direct collisions with the neutral atoms. Consequently, energy transfer takes place between plasma and neutral fluids. We describe the mode coupling processes that lead to the energy transfer between the plasma and neutral and corresponding spectral features.

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The Effect of Wave-Particle Interactions on the Propagation of Cosmic Rays

Cited by 806 publications

References 0 publications

Modulation of low-energy cosmic rays

Modulation of low-energy cosmic rays

Collisionless Shocks in Partly Ionized Plasma with Cosmic Rays: Microphysics of Non-thermal Components

Dynamics of Alfvén waves in partially ionized astrophysical plasmas

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