Elements of the TF coils that I visited: Number of coils: 16 for ARIES-AT configuration. The maintenance ports are located between the adjacent coils. Shape: In the algorithm that I used so far, the shape is a somewhat arbitrary “D”, which I scaled to look like the one from the ARIES-AT as much as possible. For the new algorithm, I chose the Princeton-D shape, which is based on the requirement of constant tension in the coil. The equation of the shape is implicit but easily solvable numerically. Thickness in the r-z plane: Determined by the superconductor peak field limit and the current density limit. The area used for definition of the current density may not be correct, since the coils are not immediately next to each other. Instead, there is a wide gap between coils occupied by the maintenance port. Width in the r-q plane: This dimension is completely vague to me. It seems to be determined only by the space left in between the maintenance ports. I think it should be determined by the current density limit, just like the thickness in the r-z plane. Materials: The ARIES-AT design book currently specifies 3 layers of materials within the TF coil. Those are the winding pack: (72% Inconel, 7% Y1Ba2Cu3O5, 7% CeO2, 0.5% Ag, 13.5% GFF Polyimide) and two coil cases around it (95% 304SS, 5% LN). Is the material up to date and are we going to use it for our studies? If not, what other materials should we consider?

Shape of the TF Coil Present Systems Algorithm ARIES-AT Design Princeton-D coil shape I propose to implement the Princeton-D shape (far right) since it resembles the ARIES-AT design much better than the present algorithm. The curve on the right is generated numerically, by using 100 data points, which took an insignificant amount of time.

Thickness in the r-z plane and width in the r-q plane. Inboard radial thickness is estimated by the procedure shown by Chuck at the last meeting: ITF = BT x 2R / (oNTF) RTFout = R - a - SOL - FW - gap1 - blkt - gap2 - shld - gap3 - VV - gap4 BTmax = oNTFITF / 2RTFout If BTmax > 21 T, reject operating point JTFoverall = [0.9 x all - (Btmax)2 / 2o] / [all x (1/JSC +1/Jcu + (R Btmax / ) x ln(RTFoutboard / RTFinboard) - Cu / Jcu] ATF = NTFITF / JTFoverall RTFin = √[(RTFout) - ATF / ] The formulas highlighted in red define the coil inboard radial thickness but do not take into account that the coils are not adjacent to each other. There is nothing that specifies the coil width.