説明
<jats:title>Abstract</jats:title> <jats:p>The parametric instability of two-dimensional Alfvénic turbulence has been studied via direct numerical simulations of magnetohydrodynamics. A general form for an Alfvénic fluctuation is derived, with a strongly anisotropic spectrum with respect to a mean magnetic field, typical of the solar wind. Perturbing this solution, an exponential growth of both compressive and backward-propagating Alfvénic fluctuations has been observed. At variance with previous 1D studies, it has been observed that the growth rate tends to increase with the plasma <jats:italic>β</jats:italic>. Unstable modes manifest as strongly localized, coherent, field-aligned, stream-like structures, with anticorrelation between magnetic and density fluctuations, in agreement with observations. These results might help us to understand the development of turbulence in the solar wind as well as in stellar winds.</jats:p>
収録刊行物
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- The Astrophysical Journal
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The Astrophysical Journal 880 (2), 156-, 2019-08-01
American Astronomical Society