Abstract
During the emerging phase of sunspot pores strong downdrafts are observed in photospheric lines, whereas the upward flow is not detected within the observational accuracy. For the study of the origin of these downdrafts, we present the numerical solutions of non-steady hydrodynamic equations in one dimension along the rising magnetic flux tubes. In these solutions, it is assumed that the solar gas inside the tube is initially in the hydrostatic HSRA and then the tube rises with a given velocity and configuration. The results reproduce well the observed radial velocity distributions, hence it is concluded that the observed strong downdrafts originate from the sliding matter along the rising magnetic flux tubes.
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Shibata, K. On the origin of strong downdrafts associated with the birth of sunspots. Sol Phys 66, 61–70 (1980). https://doi.org/10.1007/BF00150518
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DOI: https://doi.org/10.1007/BF00150518