\vnvcase[CASE1:] 
\vnvitem The arc attachment radius on the cathode is assumed to be equal to 1.5 mm;
\vnvitem On this attachment zone we assume a zero flux condition which allows the electrical conduction continuity.

\vnvcase[CASE2:] 
\vnvitem The arc attachment radius on the cathode is assumed to be equal to 2 mm;
\vnvitem On this attachment zone we assume a zero flux condition which allows the electrical conduction continuity.

\vnvcase[CASE3:]
\vnvitem The arc attachment radius on the cathode is assumed to be equal to 1.5 mm;
\vnvitem Imposed flux condition: we assume $5.10^{7}$ W/m2 on the cathode.
