Superconducting Wire and Cable Properties

In ROXIE there are two files for supderconducting wire and cable data. The older one is the roxie.madata-file. With the introduction of time-transient effects in superconductors, the cable-specific information provided in the roxie.madata-file was no longer sufficient. The roxie.cadata-file was thus introduced with a modular feature-based structure.

MADATA file

The MAterial DATA file is a database for the definition of the geometrical and superconducting properties of wires and cables. The roxie.madata-file can be edited from the Xroxie window by choosing "Open material data window (roxie.madata)" from the "Run"-menu.

The data is organized in five lines. Line one yields a "comment" in single inverted commas. Line two gives the material- (conductor-) name. Line three has geometrical data of the conductor, line four gives data of the superconducting strands in the conductor and line five yields information on the linear approximation of the critical surface around a reference working-point. A data block has the following layout:

’COMMENT’

’MATERIAL’

HEIGHT , INNER WIDTH , OUTER WIDTH , RADIAL INS. , AZIMUTH INS.

NO. STRANDS , DIA OF STRAND , CU/SC RATIO , CABLING ANGLE

TEMP , BCREF , JC/BCREF , DJC/DB

The data entries in lines 3-5 are not actually comma- but space-delimitted. There is a TCL/TK graphical user interface to edit the roxie.madata-file. For legacy-reasons the GUI, however, only displays data up to the DIA OF STRAND-entry. For SC-related data the user needs to edit the roxie.madata-file in an editor.

CADATA file

The CAble-DATA file stores information on different cable types, mostly but not exclusively, Rutherford-type superconducting cables. The roxie.cadata-file has been created as a replacement for the roxie.madata-file. The new file format holds more information than the roxie.madata-file in a structured way by the definition of "features". As a consequence, calculations that require additional input data, e.g., time-transient effects in SC cables, can only be performed if the conductor has an entry in the roxie.cadata-file. Double-entries in roxie.madata- and roxie.cadata-files are handled by giving priority to the roxie.cadata-entry. The roxie.cadata-file can be edited in a GUI that is opened by selecting "Open cable data window (roxie.cadata)" from the "Run" menu in Xroxie.

The roxie.cadata-file is organized in blocks. The idea behind the roxie.cadata-file is to create a modular database in which, e.g., several conductors can use the same insulation data or critical surface fit. The final definition of a conductor consists of an identification of insulation-type, cable-type, etc. by their (user-defined) names rather than by specifying all input-data for each conductor.

The roxie.cadata-file can be edited by selecting the "Open cable data window (roxie.cadata)"-item from the "Run"-menu.

Each block (INSUL, REMFIT, FILAMENT, STRAND, TRANSIENT, CABLE, CONDUCTOR) in the roxie.cadata-file starts with a new line BLOCK_NAME X where X is the a number of lines to follow. Then follows the data table, ended by a comment line where the variable (feature) names are defined.

INSUL block

The INSUL-block contains data on the conductor insulation. Each row contains the following data:

Variable	Type	Description
No	Integer	Row number.
Name	String	Insulation name.
Radial	Double	Radial insulation.
Azimut	Double	Azimuthal insulation.
Comment	String	Comment in single inverted commas.

REMFIT block

The REMFIT-block contains data on the critical surface fit for the superconductor. REM stands for 'remanent magnetization'. Each row of the table contains the following data:

Variable	Type	Description
No	Integer	Row number.
Name	String	FIT name.
Type	Integer	Type of FIT.
DJSC	Double	FIT parameter 1.
T_C0	Double	FIT parameter 2.
Alpha	Double	FIT parameter 3.
Beta	Double	FIT parameter 4.
Gamma	Double	FIT parameter 5.
C0	Double	FIT parameter 6.
BC20	Double	FIT parameter 7.
Comment	String	Comment in single inverted commas.

FILAMENT block

The FILAMENT-block contains data on SC filaments. Each row yields the following data:

Variable	Type	Description
No	Integer	Row number.
Name	String	Filament name.
fildiao	Double	Outer diameter of the filament [$mu$m].
fildiai	Double	Inner diameter of the filament (e.g., fil. with copper core) [$\mu$m].
*fit		*
fit perp	String	Name of the critical surface fit for orthogonal direction 2.
Comment	String	Comment in single inverted commas.

Two different fits are foreseen for anisotropic persistent current calculations. This is not yet implemented. For the time being both values should be the same. The fit names have to be names specified in the REMFIT block.

STRAND block

The STRAND-block contains data on the SC strands. Each row yields the following data:

Variable	Type	Description
No	Integer	Row number.
Name	String	Strand name.
diam.	Double	Strand diameter [mm].
cu/sc	Double	Copper to superconductor ratio.
RRR	Double	Triple-R value.
Tref	Double	Reference temperature [K].
Bref	Double	Reference $B$-field [T].
Jc(BrTr)	Double	Critical current density [$\mathrm{MA}/\mathrm{m}^2$].
dJc/dB	Double	Slope of critical surface with respect to $B$.
Comment	String	Comment in single inverted commas.

The last four entries define a linear approximation of the critical surface around a working point. This data is used for the calculation of the position on the load line which is automatically performed when the "Peak Field in Coil"-option in the "Global Information"-widget is switched 'on'. Historically, this is an older piece of code. For the new version of quench-margin calculations the "Quench and Temp. margin"-option in the "Global Information"-widget must be switched 'on'. This option uses the critical surface fit defined in the REMFIT-block.
The reference temperature of the working-point approximation is not used for the "Quench and Temp. margin"-option in the "Global Information"-widget. This option uses the "T_0"-entry in the CONDUCTOR block instead.

TRANSIENT block

The TRANSIENT-block contains data on the material properties for time-transient effects. Each row yields the following data:

Variable	Type	Description
No	Integer	Row number.
Name	String	Transient parameter-set name.
Rc	Double	Crossover resistance [$\Omega$].
Ra	Double	Adjacent resistance [$\Omega$].
fil.twistp.	Double	Filament twistpitch [m].
fil.R0	Double	Constant part of magneto-resistivity in filament matrix [$\Omega$m].
fil.dR/dB	Double	Linear part of magneto-resistivity in filament matrix [$\Omega$m/T].
strand fill.fac.	Double	Filling factor of SC-material in strand.
Comment	String	Comment in single inverted commas.

CABLE block

The CABLE-block contains data on the conductor geometry. Each row yields the following data:

Variable	Type	Description
No	Integer	Row number.
Name	String	Cable name.
height	Double	Conductor height [mm].
width_i	Double	Inner width [mm].
width_o	Double	Outer width [mm].
ns	Integer	Number of strands.
transp.	Double	Transposition pitch length [mm].
degrd	Double	Degradation factor. This option is not yet implemented.
Comment	String	Comment in single inverted commas.

Height and width is not coherently defined for superconducting cables. We denote the two slightly different narrow sides as inner and outer width.

CONDUCTOR block

The CONDUCTOR-block contains data that define the conductor using the features defined in the previous blocks. Valid features can be included by right klicking on the mouse. Each row contains the following data:

Variable	Type	Description
No	Integer	Row number.
Name	String	Conductor name.
Type	Integer	Conductor type.
Cable	String	Cable name.
Strand	String	Strand name.
Filament	String	Filament name.
Insul	String	Insulation name.
Trans	String	Transient data name.
T_0	Double	Working temperature.
Comment	String	Comment in single inverted commas.