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Shell models of RMHD turbulence and the heating of solar coronal loops

Show simple item record Buchlin, E. Velli, Marco C. 2008-07-31T22:07:22Z 2008-07-31T22:07:22Z 2007-06-10
dc.identifier.citation The Astrophysical Journal, 662:701Y714, 2007 June 10 en_US
dc.identifier.clearanceno 08-0186
dc.description.abstract A simplified nonlinear numerical model for the development of incompressible magnetohydrodynamics in the presence of a strong magnetic field B║ and stratification, nicknamed ‘‘Shell-Atm,’’ is presented. In planes orthogonal to the mean field, the nonlinear incompressible dynamics is replaced by two-dimensional shell models for the complex variables u and b, allowing one to reach large Reynolds numbers while at the same time carrying out sufficiently long integrations to obtain good statistics at moderate computational cost. The shell models of different planes are coupled by Alfve´n waves propagating along B║. The model may be applied to open or closed magnetic field configurations where the axial field dominates and the plasma pressure is low; here we apply it to the specific case of a magnetic loop of the solar corona heated by means of turbulence driven by photospheric motions, and we use statistics for its analysis. The Alfven waves interact nonlinearly and form turbulent spectra in the directions perpendicular and, through propagation, also parallel to the mean field. A heating function is obtained and shown to be intermittent; the average heating is consistent with values required for sustaining a hot corona and is proportional to the aspect ratio of the loop to the -1.5 power, and haracteristic properties of heating events are distributed as power laws. Crosscorrelations show a delay of dissipation compared with energy content. en_US
dc.description.sponsorship NASA/JPL en_US
dc.language.iso en_US en_US
dc.publisher The American Astronomical Society en_US
dc.subject magnetohydrodynamics en_US
dc.subject corona en_US
dc.subject flares en_US
dc.subject turbulence en_US
dc.title Shell models of RMHD turbulence and the heating of solar coronal loops en_US
dc.type Article en_US

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