Sudden disappearance of quiescent prominences

Cases of the breakup of quiescent prominences on July 2, 1976, and July 30, 1980, are discussed. Radio and optical data at wavelengths 1.35 and 0.8 cm and in the H-alpha line, respectively, confirmed the arch structure of the prominences. The breakup took place both through expansion of the arch and as a consequence of plasma outflow through its bases, in which heat conduction played an insignificant role.