The quality of temperature field (Table 4.1) seems to increase as
diameter increases from 4mm to 10mm. However there is a limit to
continuous diameter increment in order for tungsten rod not to serve as
heat sink to the heat shield under these prevailing physical conditions.
This heat sinking effects have been discussed in section 3. The
temperature curve is also presented in Fig.4.4 at 600A current rating
which shows time dependent temperature values. It also shows that all
selected tungsten diameters (except 10mm) have all attained steady state
temperature values within 30 seconds.