One of the important factors which stabilize the copper claded superconducting wire is boiling heat transfer from superconducting wire to liquid helium.
To improve the cooling effect of stabilized superconducting wire, the cooling effect of the channel (6.3mm wide, 12.83mm long) digged on the surface of copper was investigated. The channel oriented horizontally in liquid helium was effective in nucleate boiling heat transfer but it had little effect on maximum nucleate boiling heat flux qmax, minimum film boiling heat flux qmin and film boiling heat transfer even if it became 0.9mm deep. On the other hand, the channel oriented vertically was found effective in all over the region of cooling character curve.
In every case, there were the relatively enormous hysteresis in nucleate boiling heat transfer.