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Fountain of the Superfluid He II |
When the electric current is changed through the heater in the Superfluid He II located above the white Superleak, it is seen that the height of the He II fountain follows the current strength (i.e. the heating power). When the electric current increases the temperature of the He II, a part of the He II transforms into He I. As a result, He II flows from the lower part of the Superleak into the upper part with the heater to compensate the difference of the chemical potentials between the two parts separated by the Superleak. Since the He I cannot penetrate down through the Superleak rapidly, the liquid He overflows vigorously from the uppermost hole, like a fountain.
