The negative corona discharge phenomena occurring at a tip of water cone ha
ve been investigated focusing on the motion and the shape of the water surf
ace using a high-speed video camera. The water cone is periodically formed
from a water droplet located on a grounded electrode under de field due to
the electro-hydrodynamic instability. Negative corona discharge with trains
of Trichel-like pulses occurred just after the formation of a cone jet. Th
e magnitude and the pulse interval of the Trichel-like pulses gradually inc
rease during the period that the conical surface returns to the initial ell
ipsoidal shape. The characteristics of the Trichel pulse occurring from the
metal electrode simulating the shape of the water surface were also invest
igated. It is found that the increase in the magnitude and the interval of
the trains of Trichel-like pulses with time at the tip of water drop are ca
used by the corona discharge from the tip of the water surface that deforms
from a conical to an ellipsoidal shape. (C) 2001 Elsevier Science B.V. All
rights reserved.