Applications of Fourier analysis to broadening of stellar line profiles

Turbulence dominated by eddies of a finite size produces effects on a line profile which are similar to both macro- and micro-turbulence but which are at the same time neither. It is suggested that one of these effects in the Fourier transform domain, namely the narrowing of the first natural sidelobe relative to the width of the main lobe, can be used as an indicator of the dominance of finite-sized eddies (mesoturbulence). An examination of some existing solar data shows that finitesized eddy models fit the observed sidelobe widths better than do models computed with any reasonable combination of micro- and macro-turbulent broadenings (Paper III).