Current Density Algorithm
(without twist correction, assumes coil cross sections are ~ parallel and ~ normal to plasma)
Given:
Coil bore allowance:	CBA	13.3	cm
Turn insulation thickness	TI	0.08	cm	around each turn, assuming .0065 in glass
max current per turn	CTM	21000	Amps/turn	power supply limit
min web thickness	TWEB	1.49	cm
ground wrap thickness	TGRND	0.1	cm
minimum gap between coils	CCGAP	1	cm
no of lateral turns / pack	NTL	2	turns	always 2 turns wide per pack
cable packing fraction	CPF	0.75		from latest cable design
Assume / return from Coilopt:
Current in coil (n)	IC(n)	649600	Amps	calculated in coilopt
Min coil to coil separation	CC	10	cm	maximized in coilopt
Min coil to plasma separation	CP	19	cm	maximized in coilopt
Calculate:
Current per winding pack	ICA(n)	324800	Amps	=IC(n) /2
Current per pie	ICP(n)	162400	Amps	=IC(n) / 4
no of turns in radial dir.	NTR	8	turns	=integer(ICP/CTM)
Coil center to pack start	W1	0.84	cm	=TWEB/2+TGRND
winding to winding	W2	1.20	cm	=2*TGRND+CCGAP
Width for coil pack	WPACK	3.55	cm	=(CC-2*W1-W2)/2
Radial build for pack	RPACK	11.40	cm	=2*(CP-CBA)
gross area for pack	APACK	40.51	cm^2	=WPACK*RPACK
Insulation area	AINS	7.79	cm^2	=NTL*2*TI*RPACK+NTR*2*TI*(WPACK-2*NTL*TI)
copper area	ACU	24.54	cm^2	=(APACK-AINS)*CPF
Current density in copper	JCU	13233	A/cm^2	=ICA/ACU