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Turbulent heating of coronal active regions

Published online by Cambridge University Press:  01 September 2007

Daniel O. Gómez  and
Pablo Dmitruk
Daniel O. Gómez
Affiliation:
Department of Physics, Facultad de Ciencias Exactas y Naturales, Ciudad Universitaria, (1428) Buenos Aires, Argentina email: dgomez@df.uba.ar
Pablo Dmitruk
Affiliation:
Department of Physics, Facultad de Ciencias Exactas y Naturales, Ciudad Universitaria, (1428) Buenos Aires, Argentina email: dgomez@df.uba.ar
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Abstract

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Magnetohydrodynamic turbulence has been proposed as a mechanism for the heating of coronal active regions, and has therefore been actively investigated in recent years. According to this scenario, a turbulent regime is driven by footpoint motions. The energy being pumped this way into active region loops, is efficiently transferred to small scales due to a direct energy cascade. The ensuing generation of fine scale structures, which is a natural outcome of turbulent regimes, helps to enhance the dissipation of either waves or DC currents.

We present an updated overview of recent results on turbulent coronal heating. To illustrate this theoretical scenario, we simulate the internal dynamics of a coronal loop within the reduced MHD approximation. The application of a stationary velocity field at the photospheric boundary leads to a turbulent stationary regime after several photospheric turnover times. This regime is characterized by a broadband power spectrum and energy dissipation rate levels compatible with the heating requirements of active region loops. Also, the energy dissipation rate displays a complex superposition of impulsive events, which we associate to the so-called nanoflares. A statistical analysis yields a power law distribution as a function of their energies, which is consistent with those obtained from observations. We also study the distributions of peak dissipation rate and duration of these events.

Keywords

solar coronacoronal heatingmhd turbulencenanoflares
Type
Contributed Papers
Information
Proceedings of the International Astronomical Union , Volume 3 , Symposium S247: Waves & Oscillations in the Solar Atmosphere: Heating and Magneto-Seismology , September 2007 , pp. 269 - 278
Copyright
Copyright © International Astronomical Union 2008

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