Alphabetical list for input.cgyro

AMP

Definition

Initial amplitude of finite-\(n\) modes.

Comments

  • DEFAULT = 0.1

  • For linear simulations, the value is unimportant

  • For nonlinear runs, this will usually need to be reduced to a smaller value.

AMP0

Definition

Initial amplitude of \(n = 0\) modes.

Comments

  • DEFAULT = 0.0

BETAE_UNIT

Comments

  • DEFAULT = 0.0

Definition

The electron beta with reference to \(B_\mathrm{unit}\):

\[\beta_{e,\mathrm{unit}} \doteq \frac{8 \pi n_e T_e}{B_\mathrm{unit}^2}\]

Comments

  • DEFAULT = 0.0

BETAE_UNIT_SCALE

Definition

Scale factor for BETAE_UNIT.

Comments

  • DEFAULT = 1.0

BETA_STAR_SCALE

Definition

Pressure gradient scaling factor. Here, the pressure gradient factor is defined as

\[\beta_* = - \frac{8\pi}{B_\mathrm{unit}^2} \frac{dp}{dr}\]

Comments

  • DEFAULT = 1.0

  • In the absence of scaling, the value of \(\beta_*\) will be computed self-consistently given the value of \(\beta_{e,\mathrm{unit}}\) set in BETAE_UNIT.

  • Often it is desired to reduce \(\beta_{e,\mathrm{unit}}\) but leave the effective \(\beta_*\) unchanged. In this case, one should divide BETAE_UNIT by 2, then set BETA_STAR_SCALE=2.

BTCCW

Definition

Parameter which selects the orientation of the toroidal magnetic field \(B_t\) relative to the toroidal angle \(\varphi\).

Choices

  • BTCCW = 1: Counter-clockwise when viewed from above the torus - negative \(\mathbf{e}_{\varphi}\) for the right-handed coordinate system \((r,\theta,\varphi)\). Thus, \(B_t\) is oriented along the negative \(\mathbf{e}_{\varphi}\) direction.

  • BTCCW = -1: Clockwise when viewed from above the torus - positive \(\mathbf{e}_{\varphi}\) for the right-handed coordinate system \((r,\theta,\varphi)\). Thus, \(B_t\) is oriented along the positive \(\mathbf{e}_{\varphi}\) direction.

Comments

  • DEFAULT = -1

  • In DIII-D, typically BTCCW = 1.

  • When experimental profiles are used (PROFILE_MODEL = 2), the orientiation of \(B_t\) is inferred from input.gacode.

BOX_SIZE

Definition

Integer multiplier to determine the radial box length, \(L_x\), as a multiple of the distance between reference singular surfaces, \(L_0 = r/(qs)\).

\[\frac{L_x}{a} = \mathrm{BOX\_SIZE} \; \left( \frac{r}{qs} \right)\]

Comments

  • DEFAULT = 1 (integer)

  • Note that the reference singular surface spacing refers to \(n=1\) which is always the lowest non-zero mode in CGYRO.

  • Also, \(r \rightarrow\) RMIN, \(s \rightarrow\) S, \(q \rightarrow\) Q.

COLLISION_MODEL

Definition

Collision operator selection.

Choices

  • COLLISION_MODEL = 1: Lorentz ee+ei

  • COLLISION_MODEL = 2: Connor

  • COLLISION_MODEL = 4: Sugama (maximal accuracy)

  • COLLISION_MODEL = 5: Simple Lorentz ee+ei (fastest)

Comments

COLLISION_FIELD_MODEL

Definition

Flag to toggle self-consistent field update during collisions.

Choices

  • COLLISION_FIELD_MODEL = 0: Field update OFF

  • COLLISION_FIELD_MODEL = 1: Field update ON

Comments

  • DEFAULT = 1

COLLISION_MOM_RESTORE

Definition

Flag to toggle collisional momentum conservation.

Choices

  • COLLISION_MOM_RESTORE = 0: Momentum conservation OFF

  • COLLISION_MOM_RESTORE = 1: Momentum conservation ON

Comments

  • DEFAULT = 1

  • For test purposes only.

COLLISION_ENE_RESTORE

Definition

Flag to toggle collisional energy conservation.

Choices

  • COLLISION_ENE_RESTORE = 0: Energy conservation OFF

  • COLLISION_ENE_RESTORE = 1: Energy conservation ON

Comments

  • DEFAULT = 1

  • For test purposes only.

COLLISION_ENE_DIFFUSION

Definition

Flag to toggle collisional energy diffusion.

Choices

  • COLLISION_ENE_DIFFUSION = 0: Energy diffusion OFF

  • COLLISION_ENE_DIFFUSION = 1: Energy diffusion ON

Comments

  • DEFAULT = 1

  • For test purposes only.

COLLISION_KPERP

Definition

Flag to toggle \(k_\perp^2\) terms in collision operator.

Choices

  • COLLISION_KPERP = 0: Terms OFF

  • COLLISION_KPERP = 1: Terms ON

Comments

  • DEFAULT = 1

  • For test purposes only.

COLLISION_PRECISION_MODE

Definition

Control the precision of the cmat constants.

Choices

  • COLLISION_PRECISION_MODE = 0: Full 64-bit precision.

  • COLLISION_PRECISION_MODE = 1: Heuristics-based lower-precision setup, slightly better than 32-bit precision.

  • COLLISION_PRECISION_MODE = 32: Reduced 32-bit precision.

  • COLLISION_PRECISION_MODE = 64: Full 64-bit precision. (Same as 0)

Comments

  • DEFAULT = 0

  • Selecting COLLISION_PRECISION_MODE 1 and 32 results in significant memory saving and negligible precision loss in most use-cases.

DELTA

Definition

Triangularity, \(\delta\), of the flux surface:

Comments

  • DEFAULT = 0.0

  • This is only active with EQUILIBRIUM_MODEL = 2 (the Miller equilibrium model).

  • When experimental profiles are used (PROFILE_MODEL = 2), the triangularity as a function of radius is read from input.gacode.

DELTA_T

Definition

Simulation timestep \((c_s/a) \Delta t\).

Comments

  • DEFAULT = 0.01

  • Because CGYRO uses an explicit time-integration scheme for collisionless terms, the timestep must typically be smaller than for long-wavelength GYRO simulations.

DELTA_T_METHOD

Definition

Control for adaptive or fixed time-stepping.

Choices

  • DELTA_T_METHOD = 0: RK4 4:4(3) [non-adaptive]

  • DELTA_T_METHOD = 1: Cash-Karp 6:5(4)

  • DELTA_T_METHOD = 2: Bogacki-Shampine 7:5(4)

  • DELTA_T_METHOD = 3: Verner 10:7(6)

Comments

  • DEFAULT = 0

  • Notation is s:o(e) where s=stages,o=order,e=order of error estimate.

DENS_*

Definition

The normalized equilibrium-scale density. First species density is DENS_1, and so on.

\[\mathrm{DENS}* = \frac{n_{*}}{n_e}\]

Commments

  • DEFAULT = \([1,0,0,\ldots]\)

  • The user should set DENS=1 for electrons.

  • When experimental profiles are used (PROFILE_MODEL = 2), the densities are automatically normalized to \(n_e\).

  • When rotation effects are included (ROTATION_MODEL = 2), this parameter is the density at the outboard midplane (\(\theta=0\)).

DLNNDR_*

Definition

The normalized equilibrium-scale density gradient scale length:

\[\mathrm{DLNNDR}\_* = -a \frac{\partial {\rm ln} n_{*}}{\partial r}\]

Commments

  • DEFAULT = \([1,1,1,\ldots]\)

  • When experimental profiles are used (PROFILE_MODEL = 2), the density as a function of radius is read from input.gacode and the gradient is computed internally. The normalizing length is the plasma minor radius.

  • When rotation effects are included (ROTATION_MODEL = 2), this parameter is the value at the outboard midplane (\(\theta=0\)).

DLNTDR_*

Definition

The normalized equilibrium-scale temperature gradient scale length:

\[\mathrm{DLNTDR}\_* = -a \frac{\partial {\rm ln} T_{*}}{\partial r} \; .\]

Commments

  • DEFAULT = \([1,1,1,\ldots]\)

  • When experimental profiles are used (PROFILE_MODEL = 2), the temperature as a function of radius is read from input.gacode and the gradient is computed internally. The normalizing length is the plasma minor radius.

  • When rotation effects are included (ROTATION_MODEL = 2), this parameter is the value at the outboard midplane (\(\theta=0\)).

DZMAG

Definition

The derivative of the elevation:

\[\frac{\partial Z_0(r)}{\partial r} \; .\]

Comments

  • DEFAULT = 0.0

E_MAX

Definition

Maximum value of (pseudospectral) dimensionless energy, \(\varepsilon_\mathrm{max}\)

Comments

  • DEFAULT = 8.0

  • Corresponds to Maxwellian factor \(\displaystyle e^{-\varepsilon_\mathrm{max}}\)

ERROR_TOL

Definition

Error tolerance for adaptive time-stepping.

Comments

  • DEFAULT = 1e-4

  • Decrease this slightly for very-high-transport cases

EQUILIBRIUM_MODEL

Definition

Flux-surface shape specification parameter.

Choices

  • EQUILIBRIUM_MODEL = 1: \(s\) - \(\alpha\)

  • EQUILIBRIUM_MODEL = 2: Miller parameterization

  • EQUILIBRIUM_MODEL = 3: General (Fourier) parameterization

Comments

  • DEFAULT = 2

  • EQUILIBRIUM_MODEL=1 is not available for experimental profiles (PROFILE_MODEL =2).

FIELD_PRINT_FLAG

Definition

Toggle printing of \(\delta A_\parallel(k_x^0,k_y,t)\) and \(\delta B_\parallel(k_x^0,k_y,t)\) .

Comments

  • DEFAULT = 0

  • Output files are bin.cgyro.kxky_apar and bin.cgyro.kxky_bpar, respectively

  • Even if this flag is set to zero, potential fluctuations \(\delta\phi(k_x^0,k_y,t)\) are written to bin.cgyro.kxky_phi

FREQ_TOL

Definition

Eigenvalue convergence tolerance for linear simulations.

Comments

  • DEFAULT = 0.001

GAMMA_E

Definition

Normalized \(\mathbf{E}\times\mathbf{B}\) shearing rate \(\displaystyle \frac{a}{c_s} \gamma_E\).

Comments

  • This is the radial electric field shear and is a global term (can’t be treated in a local simulation)

  • It it zeroed automatically in a linear simulation

  • DEFAULT = 0.0

  • See discussion on plasma rotation

GAMMA_E_SCALE

Definition

Scaling factor applied to experimental value of \(\gamma_E\) .

Comments

GAMMA_P

Definition

Normalized rotation shearing rate \(\displaystyle \frac{a}{c_s} \gamma_p\).

Comments

GAMMA_P_SCALE

Definition

Scaling factor applied to experimental value of \(\gamma_p\) .

Comments

GPU_BIGMEM_FLAG

Definition

Enable (or disable) memory intensive GPU offload.

Choices

  • GPU_BIGMEM_FLAG = 0: The slower but less GPU memory demanding CPU-only Sugama operator is used.

  • GPU_BIGMEM_FLAG = 1: The GPU-accelerated Sugama operator is used. Large memory use due to cmat.

  • GPU_BIGMEM_FLAG > 1: Less GPU memory demanding, as only 1/GPU_BIGMEM_FLAG of cmat is kept in memory at any time. Slower due to memory copies.

Comments

H_PRINT_FLAG

Definition

Toggle printing of distribution for single-mode runs.

Comments

  • DEFAULT = 0.

IPCCW

Definition

Parameter which selects the orientation of the plasma current (and thus the poloidal magnetic field \(B_p\)) relative to the toroidal angle \(\varphi\).

Choices

  • IPCCW = 1: Counter-clockwise when viewed from above the torus - negative \(\mathbf{e}_{\varphi}\) for the right-handed coordinate system \((r,\theta,\varphi)\). Thus, \(B_p\) is oriented along the negative \(\mathbf{e}_{\varphi}\) direction.

  • IPCCW = -1: Clockwise when viewed from above the torus - positive \(\mathbf{e}_{\varphi}\) for the right-handed coordinate system \((r,\theta,\varphi)\). Thus, \(B_p\) is oriented along the positive \(\mathbf{e}_{\varphi}\) direction.

Comments

  • DEFAULT = -1

  • In DIII-D, typically IPCCW = 1.

  • When experimental profiles are used (PROFILE_MODEL = 2), the orientiation of IP is inferred from input.gacode.

KAPPA

Definition

Elongation, \(\kappa\), of the flux surface.

Comments

  • DEFAULT = 1.0

  • This is only active with EQUILIBRIUM_MODEL = 2 (the Miller equilibrium model).

  • When experimental profiles are used (PROFILE_MODEL = 2), the elongation as a function of radius is read from input.gacode.

GFLUX_PRINT_FLAG

Definition

Toggle printing of global flux profiles.

Comments

KY

Definition

Selector for value of \(k_\theta \rho_s\) .

Comments

  • If N_TOROIDAL = 1, this is the simulated value of \(k_\theta \rho_s\)

  • If N_TOROIDAL > 1, this is the lowest nonzero value of \(k_\theta \rho_s\)

  • Use the output in out.cgyro.info to guide selection of KY

LAMBDA_DEBYE

Definition

LAMBDA_DEBYE_SCALE

Definition

MACH

Definition

Rotation speed (Mach number) \(M\)

Comments

MACH_SCALE

Definition

Scaling factor applied to experimental value of \(M\) .

Comments

MASS_*

Definition

The species mass normalized to deuterium mass: MASS_1, and so on.

\[{\rm MASS}\_* = \frac{m_*}{m_D} \; .\]

Commments

  • DEFAULT = \([1,1,1,\ldots]\)

  • When experimental profiles are used (PROFILE_MODEL = 2), the normalizing mass is deuterium.

  • A typical case (deuterium, carbon, electrons) would be:

    MASS_1=1.0
MASS_2=6.0
MASS_3=2.724e-4

MAX_TIME

Definition

Maximum simulation time in units of \(a/c_s\)

MOMENT_PRINT_FLAG

Definition

Toggle printing of \(\delta n_a(k_x^0,k_y,t)\) and \(\delta E_a(k_x^0,k_y,t)\) .

Comments

  • DEFAULT = 0.

MPI_RANK_ORDER

Definition

Specify the relative ordering of MPI ranks.

Choices

  • MPI_RANK_ORDER = 1: Depth-first mode

  • MPI_RANK_ORDER = 2: Breadth-first mode

Comments

  • DEFAULT = 2

  • The optimal value depends on both the hardware and the problem being run.

NONLINEAR_FLAG

Definition

Toggle inclusion of nonlinear terms.

Choices

  • NONLINEAR_FLAG=0: Nonlinear terms OFF

  • NONLINEAR_FLAG=1: Nonlinear terms ON

Comments

  • DEFAULT = 0

NL_SINGLE_FLAG

Definition

Toggle FP precision used by nonlinear terms compute.

Choices

  • NL_SINGLE_FLAG=0: Use full FP64 (double) precision for all phases, including compute and MPI communication.

  • NL_SINGLE_FLAG=1: Use FP64 (double) precision for foreard communication and compute, FP32 (single) precision for reverse communication.

  • NL_SINGLE_FLAG=2: Use FP32 (single) precision for all phases, including compute and MPI communication.

Comments

  • DEFAULT = 0

  • Use of FP32 validated for modest sized simulations.

N_FIELD

Definition

Selector for number of fluctuating fields

Choices

  • N_FIELD=1: Retain \(\delta\phi\)

  • N_FIELD=2: Retain \((\delta\phi,\delta A_\parallel)\)

  • N_FIELD=3: Retain \((\delta\phi,\delta A_\parallel,\delta B_\parallel)\)

Comments

  • DEFAULT = 1

N_GLOBAL

Definition

Control number of global output harmonics

Comments

  • DEFAULT = 4

  • Making this larger retains shorter scales in the output

NU_GLOBAL

Definition

Source rate

Comments

  • DEFAULT = 15.0

  • Making this larger increases the source rate

NUP_RADIAL

Definition

UP_THETA

Definition

NUP_THETA

Definition

Accuracy control for the poloidal discretization scheme.

Choices

  • NUP_THETA=1: 1st-order conservative upwind

  • NUP_THETA=2: 3rd-order conservative upwind

  • NUP_THETA=3: 5th-order conservative upwind

Comments

  • DEFAULT=3 (5th order)

  • The numerical scheme (conservative upwind) is modified by projecting out density and current perturbations induced by the grid-scale dissipation.

UP_ALPHA

Definition

NUP_ALPHA

Definition

NU_EE

Definition

Electron-electron collision frequency \(\nu_{ee}\), in units of \(c_s/a\).

\[\nu_{ee} = \frac{4\pi n_e e^4}{(2T_e)^{3/2} m_e^{1/2}} \,\log\Lambda \; .\]

Comments

  • DEFAULT = 0.1

  • All ion collision rates are self-consistently determined from NU_EE.

  • The recommended minimum value is NU_EE = 0.01.

N_RADIAL

Definition

Number of radial wavenumbers (radial Fourier harmonics) to retain in simulation.

Comments

  • DEFAULT = 4

  • For linear simulations with BOX_SIZE =1, this can be as small as 2, but a minimium of 4 is recommended.

  • For nonlinear simulations, we recommend N_RADIAL > \(L_x/\rho\)

  • Wavenumbers span \(p = -N , \ldots , N-1\) where \(N\) = N_RADIAL/2

N_THETA

Definition

Number of poloidal gridpoints \(\theta_i\). There is a single poloidal mesh for both the distribution function and the fields (unlike GYRO).

Comments

  • DEFAULT = 24

  • The order of accuracy of the poloidal discretization is controlled by NUP_THETA.

N_XI

Definition

Number of Legendre pseudospectral meshpoints \(\xi_i\) to retain in simulation.

Comments

  • DEFAULT = 16

  • This is the pitch-angle resolution

  • This is equivalent to number of retained Legendre polynomials

N_ENERGY

Definition

Number of generalized-Laguerre pseudospectral meshpoints \(v_i\) to retain in simulation

Comments

  • DEFAULT = 8

  • This is the energy resolution

  • This is equivalent to number of retained Laguerre polynomials

N_TOROIDAL

Definition

Number of toroidal harmonics (binormal Fourier modes).

Comments

  • Together with KY, this controls the toroidal resolution.

  • Together with TOROIDALS_PER_PROC, this controls the number of MPI processes needed.

N_SPECIES

Definition

Number of kinetic species (includes electrons and all ions).

Comments

  • DEFAULT = 1

PROFILE_MODEL

Definition

Selector for profile data input.

Choices

  • PROFILE_MODEL=1: Set local profile parameters in input.cgyro.

  • PROFILE_MODEL=2: Compute local profile parameters from data in input.gacode.

Comments

  • DEFAULT = 1

PX0

Definition

The ballooning angle parameter \(\mathrm{PX0} = \theta_0/(2\pi)\).

Comments

  • DEFAULT = 0.0

  • This is used only for linear simulations.

  • The most unstable linear mode is normally at \(\mathrm{PX0} = 0\).

  • Choose \(0 \le \mathrm{PX0} < 1\).

Q

Definition

Safety factor, \(q\), of the flux surface.

Comments

  • DEFAULT = 2.0

  • This is only active with EQUILIBRIUM_MODEL = 2 (the Miller equilibrium model).

  • When experimental profiles are used (PROFILE_MODEL = 2), the safety factor as a function of radius is read from input.gacode and the safety factor gradient is computed internally.

QUASINEUTRAL_FLAG

Definition

Enforce quasineutrality when using experimental profiles.

Choices

  • QUASINEUTRAL_FLAG=0: Use raw density data.

  • QUASINEUTRAL_FLAG=1: Reset main ion density to enforce quasineutrality.

Comments

  • DEFAULT = 1

  • This is only active when experimental profiles are used (PROFILE_MODEL = 2).

RESTART_STEP

Definition

Frequency of restart file generation

Comments

  • DEFAULT = 10

  • If PRINT_STEP=100 and RESTART_STEP=10, simulation data will be output once every 100 timesteps and restart data will be output once every 1000 timesteps (i.e., once every 10 data outputs)

RMIN

Definition

The ratio \(r/a\), where \(r\) is the minor radius and \(a\) is the radius of the LCFS.

Comments

  • DEFAULT = 0.5

RMAJ

Definition

The ratio \(R_0/a\), where \(R_0\) is the major radius and \(a\) is the radius of the LCFS.

Comments

  • DEFAULT = 3.0

ROTATION_MODEL

Definition

Choices

  • ROTATION_MODEL = 1: Weak rotation

  • ROTATION_MODEL = 2: Sonic (Sugama) rotation

Comments

  • DEFAULT = 1

S

Definition

Magnetic shear, \(s\), of the flux surface:

\[s = \frac{r}{q} \frac{\partial q}{\partial r} \; .\]

Comments

  • DEFAULT = 1.0

  • This is only active with EQUILIBRIUM_MODEL = 2 (the Miller equilibrium model).

  • When experimental profiles are used (PROFILE_MODEL = 2), the safety factor as a function of radius is read from input.gacode and the safety factor gradient is computed internally.

SHIFT

Definition

Shafranov shift, \(\Delta\), of the flux surface:

\[\Delta = \frac{\partial R_0}{\partial r} \; .\]

Comments

  • DEFAULT = 0.0

  • This is only active with EQUILIBRIUM_MODEL = 2 (the Miller equilibrium model).

  • When experimental profiles are used (PROFILE_MODEL = 2), the flux-surface-center major radius as a function of radius, \(R_0(r)\), is read from input.gacode and its derivative is computed internally.

SHAPE_COS0

Definition

0th antisymmetric moment.

  • DEFAULT = 0.0

SHAPE_S_COS0

Definition

0th antisymmetric moment shear.

  • DEFAULT = 0.0

SHAPE_COS1

Definition

1st antisymmetric moment.

  • DEFAULT = 0.0

SHAPE_S_COS1

Definition

1th antisymmetric moment shear.

  • DEFAULT = 0.0

SHAPE_COS2

Definition

2nd antisymmetric moment.

  • DEFAULT = 0.0

SHAPE_S_COS2

Definition

2th antisymmetric moment shear.

  • DEFAULT = 0.0

SHAPE_COS3

Definition

3rd antisymmetric moment.

  • DEFAULT = 0.0

SHAPE_S_COS3

Definition

3rd antisymmetric moment.

  • DEFAULT = 0.0

SHAPE_SIN3

Definition

3rd symmetric moment.

  • DEFAULT = 0.0

SHAPE_S_SIN3

Definition

3rd symmetric moment shear.

  • DEFAULT = 0.0

SILENT_FLAG

Definition

S_DELTA

Definition

Measure of the rate of change of the average triangularity of the flux surface:

\[s_\delta = r \, \frac{\partial \delta}{\partial r} \; .\]

Comments

  • DEFAULT: 0.0

  • This is only active with EQUILIBRIUM_MODEL = 2 (the Miller equilibrium model).

  • When experimental profiles are used (PROFILE_MODEL = 2), the triangularity as a function of radius is read from input.gacode and the triangularity gradient is computed internally.

S_KAPPA

Definition

Measure of the rate of change of the elongation of the flux surface:

\[s_\kappa = \frac{r}{\kappa} \frac{\partial \kappa}{\partial r} \; .\]

Comments

  • DEFAULT: 0.0

  • This is only active with EQUILIBRIUM_MODEL = 2 (the Miller equilibrium model).

  • When experimental profiles are used (PROFILE_MODEL = 2), the elongation as a function of radius is read from input.gacode and the elongation gradient is computed internally.

S_ZETA

Definition

Measure of the rate of change of the average squareness of the flux surface:

\[s_\zeta = r \, \frac{\partial \zeta}{\partial r} \; .\]

Comments

  • DEFAULT: 0.0

  • This is only active with EQUILIBRIUM_MODEL = 2 (the Miller equilibrium model).

TEMP_*

Definition

The normalized equilibrium-scale temperature. First species temperature is TEMP_1, and so on.

\[\mathrm{TEMP}\_* = \frac{T_{*}}{T_e} \; .\]

Commments

  • DEFAULT: TEMP_*= \([1,\ldots]\)

  • The user should set TEMP=1 for electrons.

  • When experimental profiles are used (PROFILE_MODEL = 2), the temperatures are automatically normalized to \(T_e\).

THETA_PLOT

Definition

The number of poloidal points for output of large fluctuation moment arrays.

Commments

  • DEFAULT: THETA_PLOT=1

  • Value should be an integer divisor of N_THETA

TOROIDALS_PER_PROC

Definition

Number of toroidal harmonics to process in a single MPI process.

Comments

  • DEFAULT: 1

  • Must be a divisor of N_TOROIDAL.

  • A higher number typically results in faster simulation on low node count.

UDSYMMETRY_FLAG

Definition

UP_RADIAL

Definition

UPWIND_SINGLE_FLAG

Definition

Control the precision of upwind communication.

Choices

  • UPWIND_SINGLE_FLAG = 0: Full 64-bit precision

  • UPWIND_SINGLE_FLAG = 1: Faster but lower 32-bit precision.

Comments

  • DEFAULT = 0

VELOCITY_ORDER

Definition

Specify the ordering inside the velocity space

Choices

  • VELOCITY_ORDER = 1: species inner loop, energy outer loop

  • VELOCITY_ORDER = 2: xi inner loop, species outer loop

Comments

  • DEFAULT = 1

  • VELOCITY_ORDER=2 drastically reduces the cost of communication, but requires MPI rank to be a multiple of both N_TOROIDAL and N_SPECIES.

  • The restart file format is specific to VELOCITY_ORDER.

Z_*

Definition

Species charge. First species charge is Z_1, and so on.

Comments

  • DEFAULT = 1

  • A typical case (deuterium, carbon, electrons) would be:

    Z_1=1
Z_2=6
Z_3=-1

Z_EFF

Definition

User-specified value for \(Z_\mathrm{eff}\).

Comments

  • DEFAULT = 1.0

  • Normally this is computed self-consistently by CGYRO, but can be set by the user

  • Enabled by setting Z_EFF_METHOD = 1

  • Only allowable with simple collision models: COLLISION_MODEL = 1 or 5

Z_EFF_METHOD

Definition

Control how \(Z_\mathrm{eff}\) is computed.

Choices

  • Z_EFF_METHOD=1: Use value for Z_EFF defined in input.cgyro (or input.gacode)

  • Z_EFF_METHOD=2: Compute Z_EFF automatically and self-consistently based on species data (recommended)

Comments

  • DEFAULT = 2

  • Only allowable with simple collision models: COLLISION_MODEL = 1 or 5

ZETA

Definition

Squareness, \(\zeta\), of the flux surface.

Comments

  • DEFAULT = 0.0

  • This is only active with EQUILIBRIUM_MODEL = 2 (the Miller equilibrium model).

  • When experimental profiles are used (PROFILE_MODEL = 2), the squareness as a function of radius is read from input.gacode.

ZF_TEST_MODE

Definition

Toggle test for time-evolution of a single \(k_x\) mode (the classic zonal flow test).

Choices

  • ZF_TEST_MODE = 0: No test (default)

  • ZF_TEST_MODE = 1: Trigger test

Comments

  • DEFAULT = 0

  • The standard test is to evolve a single radial mode (N_RADIAL=1)

  • If N_RADIAL > 1, multiple independent modes will be evolved with \(k_x \rho = 2\pi p/L\) where \(1 \le p \le\) N_RADIAL

ZMAG

Definition

The ratio \(Z_0(r)/a\), where \(Z_0\) is the elevation and \(a\) is the radius of the LCFS.

Comments

  • DEFAULT = 0.0

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