*2.2. Power Source*

Two different power sources have been used. For electrode surface cleaning a pulsed DC current of 400 A and 20 ms duration has been applied [22]. The second power generator, providing 50 Hz equivalent current with a magnitude of about 28 kA (peak value), was used for the main experiments. The arc duration varied between 3 and 8 ms, depending on the time instant of electrode separation.
