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000003285 001__ 3285 000003285 005__ 20181005175146.0 000003285 0247_ $$2DOI$$a10.3847/1538-4357/aa6c65 000003285 037__ $$aSCART-2017-0054 000003285 100__ $$aShestov, S. V. 000003285 245__ $$aNonlinear Evolution of Short-wavelength Torsional Alfvén Waves 000003285 260__ $$c2017 000003285 520__ $$aWe analyze nonlinear evolution of torsional Alfvén waves in a straight magnetic flux tube filled in with a low-β plasma, and surrounded with a plasma of lower density. Such magnetic tubes model, in particular, a segment of a coronal loop or a polar plume. The wavelength is taken comparable to the tube radius. We perform a numerical simulation of the wave propagation using ideal magnetohydrodynamics. We find that a torsional wave nonlinearly induces three kinds of compressive flows: the parallel flow at the Alfvén speed, which constitutes a bulk plasma motion along the magnetic field, the tube wave, and also transverse flows in the radial direction, associated with sausage fast magnetoacoustic modes. In addition, the nonlinear torsional wave steepens and its propagation speed increases. The latter effect leads to the progressive distortion of the torsional wave front, i.e., nonlinear phase mixing. Because of the intrinsic non-uniformity of the torsional wave amplitude across the tube radius, the nonlinear effects are more pronounced in regions with higher wave amplitudes. They are always absent at the axes of the flux tube. In the case of a linear radial profile of the wave amplitude, the nonlinear effects are localized in an annulus region near the tube boundary. Thus, the parallel compressive flows driven by torsional Alfvén waves in the solar and stellar coronae, are essentially non-uniform in the perpendicular direction. The presence of additional sinks for the wave energy reduces the efficiency of the nonlinear parallel cascade in torsional Alfvén waves. 000003285 536__ $$a3PRODPROBA3/$$c3PRODPROBA3/$$f3PRODPROBA3 000003285 594__ $$aSTCE 000003285 6531_ $$amagnetohydrodynamics (MHD) 000003285 6531_ $$aSun: corona 000003285 6531_ $$aSun: oscillations 000003285 6531_ $$awaves 000003285 700__ $$aNakariakov, V. M. 000003285 700__ $$aUlyanov, A. S. 000003285 700__ $$aReva, A. A. 000003285 700__ $$aKuzin, S. V. 000003285 773__ $$c64$$n2$$pThe Astrophysical Journal$$v840$$y2017 000003285 8560_ $$fsergei.shestov@observatoire.be 000003285 85642 $$ahttp://iopscience.iop.org/article/10.3847/1538-4357/aa6c65/meta 000003285 905__ $$apublished in 000003285 980__ $$aREFERD