API Reference

COCOS Structure

cocos::Int           = COCOS ID number
exp_Bp::Int          = 0 or 1, depending if psi is already divided by 2pi or not, respectively
sigma_Bp::Int        = +1 or -1, depending if psi is increasing or decreasing with Ip and B0 positive
sigma_RpZ::Int       = +1 or -1, depending if (R,phi,Z) is right-handed or (R,Z,phi), respectively
sigma_rhotp::Int     = +1 or -1, depending if (rho, theta, phi) is right-handed or (rho,phi,theta), repectively
sign_q_pos::Int      = +1 or -1, depending if q is positive or negative with Ip and B0 positive
sign_pprime_pos::Int = +1 or -1, depending if dp/dpsi is positive or negative with Ip and B0 positive

check_cocos(sigma_B0, sigma_Ip, sigma_F, sigma_pprime, sigma_q, sigma_dpsi, cc::COCOS; verbose = false) -> Bool

Returns if equilibrium quantities are consistent with given COCOS

Arguments:

• sigma_B0 - Toroidal magnetic field sign
• sigma_Ip - Plasma current sign
• sigma_F - Poloidal current sign
• sigma_pprime - Pressure gradient sign
• sigma_dpsi - dpsi/dr sign
• cc::Union{Int,COCOS} - COCOS structure or ID

check_cocos(B0, Ip, F::AbstractVector, pprime::AbstractVector, q::AbstractVector, psi::AbstracVector, cc::COCOS; verbose = false) -> Bool

Returns if equilibrium quantities are consistent with given COCOS

Arguments:

• B0 - Toroidal magnetic field
• Ip - Plasma current
• F::AbstractVector - Poloidal current as a function of psi
• pprime::AbstracVector - Pressure gradient w.r.t. psi as a function of psi
• psi::AbstractVector - Poloidal flux
• cc::Union{Int,COCOS} - COCOS structure or ID

cocos(cocos_ID) -> COCOS

Returns COCOS structure given the cocos_ID number

cylindrical_cocos(c::COCOS, r, phi, z) -> NTuple{3}

Returns the right-handed cylindrical coordinate according to the provided COCOS.

cocos.sigma_RpZ = +1 -> (r, phi, z)
cocos.sigma_RpZ = -1 -> (r, z, phi)

cylindrical_cocos_indices(c::COCOS) -> NTuple{3}

Returns the indices of the r, phi, and z coordinates, respectively, relative to the provided COCOS.

cocos.sigma_RpZ = +1 -> (1, 2, 3)
cocos.sigma_RpZ = -1 -> (1, 3, 2)

identify_cocos(sigma_B0, sigma_Ip, sigma_q, sigma_dpsi, clockwise_phi) -> List of possible COCOS IDs

Utility function to identify COCOS coordinate system. If multiple COCOS are possible, then all are returned.

Arguments:

• sigma_B0 - (+1,-1) sign of the toroidal magnetic field
• sigma_Ip - (+1,-1) sign of toroidal plasma current
• sigma_q - (+1,-1) sign of the safety factor (q) within the plasma
• sigma_dpsi - +1 if psi is increasing, -1 if psi is decreasing
• clockwise_phi::Bool - (optional) [true, false] if phi angle is defined clockwise or not. This is required to identify odd Vs even COCOS. Note that this cannot be determined from the output of a code.

identify_cocos(B0, Ip, q, psi, clockwise_phi, a)

Utility function to identify COCOS coordinate system. If multiple COCOS are possible, then all are returned.

Arguments:

• B0 - toroidal magnetic field (with sign)
• Ip - plasma current (with sign)
• q - safety factor profile (with sign) as function of psi
• psi::AbstractVector - Vector of poloidal fluxs from the magnetic axis to the plasma boundary
• clockwise_phi::Bool - (optional) [true, false] if phi angle is defined clockwise or not. This is required to identify odd Vs even COCOS. Note that this cannot be determined from the output of a code.
• a::AbstractVector - (optional) flux surfaces minor radius as function of psi. This is required to identify 2*pi term in psi definition

poloidal_cocos(c::COCOS, rho, theta, phi) -> NTuple{3}

Returns the right-handed poloidal coordinate according to the provided COCOS.

cocos.sigma_rhotp = +1 -> (rho, theta, phi)
cocos.sigma_rhotp = -1 -> (rho, phi, theta)

poloidal_cocos_indices(c::COCOS) -> NTuple{3}

Returns the indices of the rho, theta, and phi coordinates, respectively, relative to the provided COCOS.

cocos.sigma_rhotp = +1 -> (1, 2, 3)
cocos.sigma_rhotp = -1 -> (1, 3, 2)

transform_cocos(cc_in::Union{Int,COCOS}, cc_out::Union{Int,COCOS};
                sigma_Ip = nothing, sigma_B0=nothing,
                ld = (1,1), lB = (1,1), exp_mu0 = (0,0)) -> Dict

Returns a dictionary of the multiplicative factors to transform COCOS from ccin to ccout

Arguments:

• sigma_Ip::Union{NTuple{2,Int},Nothing} - A tuple of the (Input, Output) current sign or nothing
• sigma_B0::Union{NTuple{2,Int},Nothing} - A tuple of the (Input, Output) toroidal field sign or nothing
• ld::NTuple{2,<:Real} - A tuple of the (Input, Output) length scale factor. Default = (1,1)
• lB::NTuple{2,<:Real} - A tuple of the (Input, Output) magnetic field scale factor. Default = (1,1)
• exp_mu0::NTuple{2,<:Real} - A tuple of the (Input, Output) mu0 exponent (0, 1). Default = (0,0)