I added another terminal to the superconducting coil.
It looks like this:
I operated the coil in the following configuration. About 12cm of SC cable was above the liquid nitrogen forming a resistor.
Putting 5A through the SC coil produced about 20 Gauss.
When I submerged the warm SC cable in liquid nitrogen (leaving the current source on), the field dropped off by half!
The strength of the magnetic field was sensitive to changes in the amount of YBCO at room temperature.
We succeeded in directing the current into the main superconducting coil despite the short circuit. GOOD.
When we “turn off the heater” by dunking the warm SC cable into the liquid nitrogen, we lose much of the current going into the main coil.
Not exactly sure how to interpret the results.
My guesses for what’s needed:
1) Longer span of YBCO in the heater.
2) Insulate the heater.
3) Longer splice, better solder joint.