Representation of Plasma Toroidal Current

Plasma toroidal current is modeled by a number of filamentary toroidal current elements whose (r,z) locations are defined by a set of points on a (cross-sectional) grid. Available grid sizes are 33 x 33, 33 x 65, 65 x 65, and 129 x 129. (The choice of grid size is determined by which version of EFIT you run. For example, efitdu3365 uses a 33 x 65 grid.) The amount of current in each filament ("at" each grid point) is represented by JT(R,psi) = R[P'(psi) + mu0 FF'(psi)/ (4 pi2 R2)] where psi is the value of normalized flux at each grid point, and P'(psi) and FF'(psi) are represented by linear combinations of a small number of basis functions.

The variables below are used to specify the representation of the functions P' and FF' and any desired constraints on those representations. All variables are input via the IN1 or EFITIN namelists. Variables which have no defaults (and thus require inputs??) are printed in bold.

KFFFNC	Choice of basis function for FF'. 0 = polynomial representation FF'(psi)=gamma0+gamma1 psi+...+gamman psin. 1 = ?? 2 = ?? 3 = ?? 4 = ?? 5 = ?? 6 = spline respresentation.
KPPFNC	Choice of basis function for P'. 0 = polynomial representation P'(psi)=alpha0+alpha1 psi+...+alphan psim. 1 = ?? 2 = ?? 3 = ?? 4 = ?? 5 = ?? 6 = spline respresentation.
KWWFNC	Choice of basis function for POmega'. 0 = polynomial representation. 1 = ?? 2 = ?? 3 = ?? 4 = ?? 5 = ?? 6 = spline respresentation
ICPROF	Specific choice of current profile 0 = current profile is not specified by this variable (default) 1 = no edge current density allowed 2 = free edge current density 3 = weak edge current density constraint This sets some or all of the variables KFFCUR, KPPCUR, FCURBD, PCURBD, FWTBP, FWTQA, QVFIT, KCALPA, CALPA, XALPA, KCGAMA, CGAMA, and XGAMA to predefined values. NOTE that if these variables are seperately specified in the namelist input, the values set by the ICPROF variable will override them.
KPPCUR	Number of coefficients in polynomial representation of P'. Ignored when using spline representation. Default = 3
KFFCUR	Number of coefficients in polynomial representation of FF'. Ignored when using spline representation. Default = 1
KCALPA	+ = number of constraints on coefficients alpha for P' (only relevant when ICURRT=2) specified through matrix CALPA and vector XALPA. For both equilibrium and fitting. Default=0
CALPA	+ CALPA(2,i) alpha(2) +...+ CALPA(n,i) alpha(n) = XALPA(i) for i=1 to KCALPA, where n = KPPCUR. Can scale coefficients up or down relative to nominal weights of 1 to get stronger or weaker constraint, respectively. Default CALPA(13,1) = (0.1,0.1,0.1)
XALPA	Constraint vector for P' when ICURRT=2 and KCALPA>0. See CALPA.
KCGAMA	+ = number of constraints on coefficients gamma for FF' (only relevant when ICURRT=2), specified through matrix CGAMA and vector XGAMA. For both equilibrium and fitting. Default=0
CGAMA	Constraint matrix for FF' when ICURRT=2 and KCGAMA>0. Defines constraint equations of the form CGAMA(1,i) gamma(1) + CGAMA(2,i) gamma(2) +...+ CGAMA(n,i) gamma(n) = XGAMA(i) for i=1 to KCGAMA, where n = KFFCUR.
XGAMA	Constraint vector for FF' when ICURRT=2 and KCGAMA>0. See CGAMA.
KFFKNT	Number of knots for FF' in spline representation. Ignored unless KFFFNC=6.
FFKNT	FF' knot locations in normalized psi, must be between 0 and 1. Vector of length KFFKNT. Ignored unless KFFFNC=6.
FFTENS	FF' spline tension, small (e.g., 0.1) = approximately(?) cubic, large (e.g., 10.0) = approximately(?) piecewise linear. Ignored unless KFFFNC=6.
KFFBDRY	Constraint switch for FF' (0=off, 1=on) for each knot. Vector of length KFFKNT. Default 0's. Ignored unless KFFFNC=6.
FFBDRY	FF' value for each knot, used only when KFFBDRY=1. Vector of length KFFKNT. Ignored unless KFFFNC=6.
KFF2BDRY	Constraint switch for (FF')' (0=off, 1=on) for each knot. Vector of length KFFKNT. Default 0's. Ignored unless KFFFNC=6.
FF2BDRY	(FF')' value for each knot, used only when KFFBDRY=1. Vector of length KFFKNT. Ignored unless KFFFNC=6.
KPPKNT	Number of knots for P' in spline representation. Ignored unless KPPFNC=6.
PPKNT	P' knot locations in normalized psi, must be between 0 and 1. Vector of length KPPKNT. Ignored unless KPPFNC=6.
PPTENS	P' spline tension, small (e.g., 0.1) = approximately(?) cubic, large (e.g., 10.0) = approximately(?) piecewise linear. Ignored unless KPPFNC=6.
KPPBDRY	Constraint switch for P'. Vector of length KPPKNT. Ignored unless KPPFNC=6.
PPBDRY	P' at each knot location where KPPBDRY=1. Vector of length KPPKNT. Ignored unless KPPFNC=6.
KPP2BDRY	Constraint switch for (P')'. Vector of length KPPKNT. Ignored unless KPPFNC=6.
PP2BDRY	P at each knot location where KPP2BDRY=1. Vector of length KPPKNT. Ignored unless KPPFNC=6.
KWWKNT	Number of knots for POmega' in spline representation. Ignored unless KWWFNC=6.
WWKNT	array of POmega' knot locations in normalized psi for spline basis function, must be between 0 and 1. Vector of length KWWKNT. Ignored unless KWWFNC=6.
WWTENS	POmega' spline tension, small (e.g., 0.1) = approximately(?) cubic, large (e.g., 10.0) = approximately(?) piecewise linear. Ignored unless KWWFNC=6.
KWWBDRY	Constraint switch for POmega'. Vector of length KWWKNT. Ignored unless KWWFNC=6.
WWBDRY	POmega' at each knot location where KWWBDRY=1. Vector of length KWWKNT. Ignored unless KWWFNC=6.
KWW2BDRY	Constraint switch for POmega. Vector of length KWWKNT. Ignored unless KWWFNC=6.
WW2BDRY	POmega at each knot location where KWWBDRY=1. Vector of length KWWKNT. Ignored unless KWWFNC=6.