Hydraulic Concentration of Magnetic Fields in the Solar Photosphere. II. Bernoulli Effect

The magnetic filaments in the solar photosphere are subject to vigorous kneading and massaging by the convective turbulence at, and beneath, the visible surface. It is shown that the Bernoulli effect of the consequent surging of fluid up and down along the filaments is a major factor in concentrating the magnetic pressure of the filament (the mean square field). The mean field is also increased if the phase velocity of the external massaging exceeds the Alfven speed within the filament. The net observational magnetic result of the surging, then, depends upon the response of the observing instrument, and whether it essentially observes the mean field, the rms field, or whether there are saturation effects. The hydraulic effects responsible for the formation of the concentrated magnetic filaments are part of the dynamical picture of spicules, pointed out a decade ago. Hence we suggest that the chromospheric mottles (spicules) seen in Ha are in fact the intense magnetic filaments that carry most of the magnetic flux across the photospheric boundary of the Sun. Subject headings: granules and supergranules, solar - hydromagnetics - magnetic fields, solar