Анотація:
Instability of the flat surface of a thin liquid layer wetting a solid substrate under inverted
gravitation conditions is discovered. The development of this instability leads to formation of a
new stationary nonuniform liquid surface state. It looks like a solitary hill with characteristics
sensitive to the liquid film parameters, particularly to the layer thickness at which the instability
begins to develop. By application of a variational approach the mechanical stability of such a hill
(droplet) in the one-dimensional approximation is proved. A variational picture of the shape evolution
for a cylindrical charged droplet in an external electric field is constructed, too. The results
obtained are compared with an experiment on liquid hydrogen droplets [A.A. Levchenko, G.V.
Kolmakov, L.P. Mezhov-Deglin, M.G. Mikhailov, and A.B. Trusov, Low Temp. Phys. 25, 242
(1999)]. The theory developed is in good agreement with the results of experiments.