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Title: Analytical approximation of transit time scattering due to magnetosonic waves: BORTNIK ET AL.

 [1];  [1];  [2];  [3]
  1. Department of Atmospheric and Oceanic Sciences, University of California, Los Angeles California USA
  2. Department of Space Physics, School of Electronic Information, Wuhan University, Wuhan China
  3. Institute of Space Physics and Applied Technology, Peking University, Beijing China
Publication Date:
Sponsoring Org.:
OSTI Identifier:
Grant/Contract Number:
Resource Type:
Journal Article: Publisher's Accepted Manuscript
Journal Name:
Geophysical Research Letters
Additional Journal Information:
Journal Volume: 42; Journal Issue: 5; Related Information: CHORUS Timestamp: 2017-10-23 17:51:11; Journal ID: ISSN 0094-8276
Wiley Blackwell (John Wiley & Sons)
Country of Publication:
United States

Citation Formats

Bortnik, J., Thorne, R. M., Ni, B., and Li, J. Analytical approximation of transit time scattering due to magnetosonic waves: BORTNIK ET AL.. United States: N. p., 2015. Web. doi:10.1002/2014GL062710.
Bortnik, J., Thorne, R. M., Ni, B., & Li, J. Analytical approximation of transit time scattering due to magnetosonic waves: BORTNIK ET AL.. United States. doi:10.1002/2014GL062710.
Bortnik, J., Thorne, R. M., Ni, B., and Li, J. 2015. "Analytical approximation of transit time scattering due to magnetosonic waves: BORTNIK ET AL.". United States. doi:10.1002/2014GL062710.
title = {Analytical approximation of transit time scattering due to magnetosonic waves: BORTNIK ET AL.},
author = {Bortnik, J. and Thorne, R. M. and Ni, B. and Li, J.},
abstractNote = {},
doi = {10.1002/2014GL062710},
journal = {Geophysical Research Letters},
number = 5,
volume = 42,
place = {United States},
year = 2015,
month = 3

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1002/2014GL062710

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Cited by: 10works
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  • We have analyzed the amplification of slow magnetosonic (or pseudo-Alfvenic) waves (SMW) in incompressible shear flow. As found here, the amplification depends on the component of the wave-vector perpendicular to the direction of the shear flow. Earlier numerical results are consistent with the general analytic solution for the linearized magnetohydrodynamic equations, derived here for the model case of pure homogeneous shear (without Coriolis force). An asymptotically exact analytical formula for the amplification coefficient is derived for the case when the amplification is sufficiently large.
  • Scattering of fast magnetosonic waves off interchange modes is studied using a weak coupling, mode--mode dispersion relation. This process can lead to stabilization of interchange modes if certain specified conditions on the fast wave electric field strength and on the wave vectors of the interacting modes are satisfied.
  • In this paper, we study relativistic electron scattering by fast magnetosonic waves. We compare results of test particle simulations and the quasi-linear theory for different spectra of waves to investigate how a fine structure of the wave emission can influence electron resonant scattering. We show that for a realistically wide distribution of wave normal angles θ (i.e., when the dispersion δθ≥0.5{sup °}), relativistic electron scattering is similar for a wide wave spectrum and for a spectrum consisting in well-separated ion cyclotron harmonics. Comparisons of test particle simulations with quasi-linear theory show that for δθ>0.5{sup °}, the quasi-linear approximation describes resonantmore » scattering correctly for a large enough plasma frequency. For a very narrow θ distribution (when δθ∼0.05{sup °}), however, the effect of a fine structure in the wave spectrum becomes important. In this case, quasi-linear theory clearly fails in describing accurately electron scattering by fast magnetosonic waves. We also study the effect of high wave amplitudes on relativistic electron scattering. For typical conditions in the earth's radiation belts, the quasi-linear approximation cannot accurately describe electron scattering for waves with averaged amplitudes >300 pT. We discuss various applications of the obtained results for modeling electron dynamics in the radiation belts and in the Earth's magnetotail.« less
  • Landau`s original derivation of the collisionless damping of small-amplitude Langmuir waves in an infinite homogeneous plasma relied on the introduction of complex velocities and was therefore somewhat difficult to interpret physically. This has inspired many subsequent derivations of Landau damping that involve only real physical quantities throughout. These ``physical`` derivations, however, have required the calculation of quantities to second order in the wave field, whereas Landau`s approach involved only first-order quantities. More recent generalizations of Landau damping to localized fields, often called ``transit-time damping,`` have followed the physical approach, and thus also required second-order calculations, which can be quite lengthy.more » In this paper it is shown that when the equilibrium distribution function depends solely on the energy, invoking the time-reversal invariance of the Vlasov equation allows transit-time damping to be analyzed using only first-order physical quantities. This greatly simplifies the calculation of the damping of localized plasma waves and, in the limit of an infinite plasma, provides a derivation of Landau damping that is both physical and linear in the wave field. This paper investigates the transit-time damping of plasma waves confined in slabs, cylinders, and spheres, analyzing the dependence on size, radius, and mode number, and demonstrating the approach to Landau damping as the systems become large. It is also shown that the same approach can be extended to more general geometries. A companion paper analyzes transit-time damping in a cylinder in more detail, with applications to the problem of stimulated Raman scattering in self-focused light filaments in laser-produced plasmas. {copyright} {ital 1998 American Institute of Physics.}« less
  • A Fokker{endash}Planck theory is developed to describe the diffusion in momentum space of a beam of relativistic electrons due to multiple transit-time interactions with an ensemble of coherent Langmuir wave packets. The theory incorporates two ingredients: a perturbed-orbit calculation of the momentum change of a test particle during a single transit-time interaction, and an ensemble average of the resulting Fokker{endash}Planck coefficients based on the statistical properties of strong Langmuir turbulence. An approximate analytic solution of the Fokker{endash}Planck equation is obtained for the case of a strongly collimated beam, and is used to interpret measurements of energy and pitch-angle scattering inmore » relativistic-electron-beam (REB) experiments. Fokker{endash}Planck coefficients are also calculated for a weakly collimated beam. It is shown that the theory correctly predicts the amount of energy scattering in REB experiments, but underestimates the pitch-angle scattering regardless of the distribution of wave packet orientations and the degree of collimation of the beam. This discrepancy may be a product of the approximate wave-packet structure assumed in the analysis, or of systematic errors in the experimental data; alternatively, it may imply that a non-transit-time process is responsible for part of the pitch-angle scattering observed. {copyright} {ital 1996 American Institute of Physics.}« less