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| Paper: |
Excitation of Slow-Modes in Network Magnetic Elements |
| Volume: |
455, 4th Hinode Science Meeting: Unsolved Problems and Recent Insights |
| Page: |
237 |
| Authors: |
Kato, Y.; Steiner, O.; Steffen, M.; Suematsu, Y. |
| Abstract: |
From radiation magnetohydrodynamic (RMHD)
simulations of the solar atmosphere we have found a new mechanism for
the excitation of longitudinal slow modes within magnetic flux
concentrations. It is found that the convective downdrafts in the
immediate surroundings of magnetic elements are responsible for the
excitation of slow modes. The coupling between the external downdraft
and the plasma motion internal to the flux concentration is mediated
by the inertial forces of the downdraft that act on the magnetic flux
concentration. These forces pump the internal atmosphere in the
downward direction, which entails a fast downflow in the photospheric
and chromospheric layers of the magnetic element. Subsequent to the
transient pumping phase, the atmosphere rebounds, causing a slow mode
traveling along the magnetic flux concentration in the upward
direction and developing into a shock wave in chromospheric heights,
possibly capable of producing some kind of dynamic fibril. This event
occurs recurrently. We compare the power spectra of the temperature
and velocity of the flux-sheet atmosphere to the corresponding spectra
of the unmagnetized atmosphere. |
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