Origin of quiescent prominences

For stable equilibrium, prominences must be supported with magnetic lines of force leaning upon the photosphere and concave in their tops; however the general structure may be more complicated. If such a field appears in the corona, the heating of the gas near the upper pit should be low, because Alfvén and slow waves do not propagate across magnetic lines and fast mode waves attenuate because of refraction. The gas of the corona, distributed along the magnetic lines tube, cannot keep balance, it should flow down in the pit, condense there and fall down into the chromosphere in some places. The prominence, therefore, originates in the matter of the chromosphere which is situated at the other end of the magnetic lines and flows through the corona under the effect of a siphon-type mechanism. A similar mechanism for chromospheric structures was earlier suggested by Meyer and Schmidt. A stationary stream along the tube has been calculated with allowance for the heat conductivity and radiative cooling of the corona gas. The stream is subsonic and is about 10¹⁵ cm⁻² sec⁻¹ which corresponds to the prominence formation time of the order of a day.