  The paper presents an experimental study of the capillary electrostatic
instability occurring under effect of a constant electric field on a magnetic
fluid individual peak. The peaks under study occur at disintegration of a
magnetic fluid layer applied on a flat electrode surface under effect of a
perpendicular magnetic field. The electrocapillary instability shows itself as
an emission of charged drops jets from the peak point in direction of the
opposing electrode. The charged drops emission repeats periodically and results
in the peak shape pulsations. It is shown that a magnetic field affects the
electrocapillary instability occurrence regularities and can stimulate its
development. The critical electric and magnetic field strengths at which the
instability occurs have been measured; their dependence on the peak size is
shown. The hysteresis in the system has been studied; it consists in that the
charged drops emission stops at a lesser electric (or magnetic) field strength
than that of the initial occurrence. The peak pulsations frequency depending on
the magnetic and electric field strengths and on the peak size has been
measured.
