Laitinen, Timo Lauri Mikael, Dalla, Silvia, Kelly, J. and Marsh, Michael (2013) ENERGETIC PARTICLE DIFFUSION IN CRITICALLY BALANCED TURBULENCE. The Astrophysical Journal, 764 (2). pp. 168-176. ISSN 0004-637X
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Official URL: http://dx.doi.org/10.1088/0004-637x/764/2/168
Observations and modeling suggest that the fluctuations in magnetized plasmas exhibit scale-dependent anisotropy, with more energy in the fluctuations perpendicular to the mean magnetic field than in the parallel fluctuations and the anisotropy increasing at smaller scales. The scale dependence of the anisotropy has not been studied in full-orbit simulations of particle transport in turbulent plasmas so far. In this paper, we construct a model of critically balanced turbulence, as suggested by Goldreich & Sridhar, and calculate energetic particle spatial diffusion coefficients using full-orbit simulations. The model uses an enveloped turbulence approach, where each two-dimensional wave mode with wavenumber k ⊥ is packed into envelopes of length L following the critical balance condition, Lk –2/3 ⊥, with the wave mode parameters changing between envelopes. Using full-orbit particle simulations, we find that both the parallel and perpendicular diffusion coefficients increase by a factor of two, compared to previous models with scale-independent anisotropy.
|Uncontrolled Keywords (separate with ;):||cosmic rays; diffusion; turbulence;|
|Subjects:||Mathematics > Pure mathematics|
Physical sciences > Physics
|Schools:||Faculty of Science and Technology > School of Physical Sciences and Computing > Jeremiah Horrocks Institute|
|Deposited By:||Nuala Jones|
|Deposited On:||05 Mar 2013 13:14|
|Last Modified:||24 Oct 2016 09:10|
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