Amplitudes and energy fluxes of simulated decayless kink oscillations. (arXiv:1906.02001v1 [astro-ph.SR])
<a href="http://arxiv.org/find/astro-ph/1/au:+Karampelas_K/0/1/0/all/0/1">K. Karampelas</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Doorsselaere_T/0/1/0/all/0/1">T. Van Doorsselaere</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Pascoe_D/0/1/0/all/0/1">D. J. Pascoe</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Guo_M/0/1/0/all/0/1">M. Guo</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Antolin_P/0/1/0/all/0/1">P. Antolin</a>
Recent observations with the Atmospheric Imaging Assembly (AIA) instrument on
the SDO spacecraft have revealed the existence of decayless coronal kink
oscillations. These transverse oscillations are not connected to any external
phenomena like flares or coronal mass ejections, and show significantly lower
amplitudes than the externally excited decaying oscillations. Numerical studies
have managed to reproduce such decayless oscillations in the form of footpoint
driven standing waves in coronal loops, and to treat them as a possible
mechanism for wave heating of the solar corona. Our aim is to investigate the
correlation between the observed amplitudes of the oscillations and input the
energy flux from different drivers. We perform 3D MHD simulations in single,
straight, density-enhanced coronal flux tubes for different drivers, in the
presence of gravity. Synthetic images at different spectral lines are
constructed with the use of the FoMo code. The development of the
Kelvin-Helmholtz instability leads to mixing of plasma between the flux tube
and the hot corona. Once the KHI is fully developed, the amplitudes of the
decayless oscillations show only a weak correlation with the driver strength.
We find that low amplitude decayless kink oscillations may correspond to
significant energy fluxes of the order of the radiative losses for the Quiet
Sun. A clear correlation between the input energy flux and the observed
amplitudes from our synthetic imaging data cannot be established. Stronger
drivers lead to higher vales of the line width estimated energy fluxes.
Finally, estimations of the energy fluxes by spectroscopic data are affected by
the LOS angle, favoring combined analysis of imaging and spectroscopic data for
single oscillating loops.
Recent observations with the Atmospheric Imaging Assembly (AIA) instrument on
the SDO spacecraft have revealed the existence of decayless coronal kink
oscillations. These transverse oscillations are not connected to any external
phenomena like flares or coronal mass ejections, and show significantly lower
amplitudes than the externally excited decaying oscillations. Numerical studies
have managed to reproduce such decayless oscillations in the form of footpoint
driven standing waves in coronal loops, and to treat them as a possible
mechanism for wave heating of the solar corona. Our aim is to investigate the
correlation between the observed amplitudes of the oscillations and input the
energy flux from different drivers. We perform 3D MHD simulations in single,
straight, density-enhanced coronal flux tubes for different drivers, in the
presence of gravity. Synthetic images at different spectral lines are
constructed with the use of the FoMo code. The development of the
Kelvin-Helmholtz instability leads to mixing of plasma between the flux tube
and the hot corona. Once the KHI is fully developed, the amplitudes of the
decayless oscillations show only a weak correlation with the driver strength.
We find that low amplitude decayless kink oscillations may correspond to
significant energy fluxes of the order of the radiative losses for the Quiet
Sun. A clear correlation between the input energy flux and the observed
amplitudes from our synthetic imaging data cannot be established. Stronger
drivers lead to higher vales of the line width estimated energy fluxes.
Finally, estimations of the energy fluxes by spectroscopic data are affected by
the LOS angle, favoring combined analysis of imaging and spectroscopic data for
single oscillating loops.
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