The stability of spatial periodization of primary energy release regions in solar flares is studied based on extreme ultraviolet observations by the TRACE spacecraft. Fourier analysis of difference images shows the presence of several harmonics in the spatial distribution of energy release regions of the November 4, 2003 flare. Characteristic spatial periods lie in the range from 3 to 18 Mm. According to modern concepts, such periodization can be the result of the decay of the preflare current sheet, accumulating solar flare energy in coronal magnetic fields, due to some instability, for example, of a thermal nature. On the contrary, the periodization of the Bastille Day flare on July 14, 2000, being on the same spatial scales, did not demonstrate such stability.
L. S. Ledentsov (Mon,) studied this question.