## YBCO (updated)

6 02 2009

I’ve updated this post with help from Msimon.

Here is the spec sheet for the YBCO I ordered, specifically 13 meters of SCS4050i.

Icvalues range from 80 –110 Amps at 77 K in 4 mm width

Engineering Current Density (Je) = 21 –29 kA/cm2

Now I’m going to walk through some calculations(full code here) based on a dodecahedral bussard reactor core about the size of a basketball (outside diameter of core is ~200 mm). Dimensions:
``` outside_radius: 99.9393315967242 mm```

`torus_midplane_radius: 79.4172368111867 mm`

`torus_radius: 34.62 mm`

```torus_circumference: 217.524 mm ```

For now I’m ignoring the effects of the critical magnetic field. In these ruby code samples, the “>>” indicates converting physical units.

We have 13 meter of 4mm YBCO. This allows for 4 turns for each of the 12 coils:

`turns = ((ybco_length >> Unit("mm"))/torus_circumference/12).floor # 4 turns for each coil`

The superconducting tape supports a critical current of ~100 amps. So with 4 turns, we have 400 Ampere-turns per coil. Plug this into Ampère’s force law and you get 0.021912 N or force, or 2.235 grams.