ABSTRACT
Experimental evidence has confirmed that the so called transfer functions, the power flux density q(Te ,U,) and the total current density j(Te ,U,), are appropriate tools to model the different modes of cathodic arc attachment [1, 2]. Te is the local cathode surface temperature and U, the cathode fall which is taken constant along the whole cathodic plasma boundary layer (CPBL). Transfer functions were calculated in [1] for Ne, Ar, Kr and Xe for different gas pressures p and work functions ca and applied in [2] to simulate the behaviour of cylindrical cathode rods by an integration of the cathodic power balance [3]. A model ]amp was developed to perform reproducible measurements at HID lamp electrodes in which the electrodes can be observed thoroughly and can be displaced very precisely [4]. In this lamp by probe measurements electrode falls could be specified [1, 5]. By pyrometric measurements electrode temperatures Te , the power consumption of the cathodes Pe and also cathode falls Ue [2, 4] were determined. And by spatially resolved spectroscopic measurements at the plasma in front of the electrode [6] electron temperatures Te and electron densities 11, were found.
