Plasma Parameters, Fields, and Distributions

  1. User Guide
  2. Physics
  3. Plasma Parameters, Fields, and Distributions

Plasma Parameters and Fields

It is common in Tokamaks to input the plasma parameters and fields as flux functions. However, this approach makes several assumptions that may not be true in non-tokamak devices. The default settings of FIDASIM are to map the plasma parameters and fields onto the 2D R-Z grid. If the user inputs any Phi variable information, the plasma parameters and fields will be mapped onto a 3D R-Z-Phi cylindrical grid. Furthermore, a boolean mask is used to indicate where the plasma and fields are well defined.

FIDASIM reads the plasma parameters and fields from an HDF5 file structured as follows...

[runid]_equilibrium.h5
├── plasma
└── fields

where the plasma group has the following datasets

Variable Type Rank Dimensions Units Description
nr Int16 0 NA NA Number of radii
nz Int16 0 NA NA Number of z values
nphi Int16 0 NA NA Number of phi values (Optional)
nthermal Int16 0 NA NA Number of hydrogenic, thermal ion species
impurity_charge Int16 0 NA NA Main impurity charge number
species_mass Float64 1 [nthermal] amu Thermal ion species mass
r Float64 1 [nr] cm Array of radii
z Float64 1 [nz] cm Array of z values
phi Float64 1 [nphi] rad Array of phi values (Optional)
r2d Float64 2/3 [nr,nz[,nphi]] cm 2D/3D array of radii r = r2d(r,z[,phi])
z2d Float64 2/3 [nr,nz[,nphi]] cm 2D/3D array of z values z = z2d(r,z,[phi])
time Float64 0 NA s Time when the plasma parameter data was collected
data_source String 0 NA NA Source of the plasma parameter data
mask Int16 2/3 [nr,nz[,nphi]] NA Boolean mask that indicates where the plasma is well defined
te Float64 2/3 [nr,nz[,nphi]] keV Electron temperature
ti Float64 2/3 [nr,nz[,nphi]] keV Ion temperature
dene Float64 2/3 [nr,nz[,nphi]] cm^-3 Electron density
denimp Float64 2/3 [nr,nz[,nphi]] cm^-3 Impurity density
deni Float64 3/4 [nthermal,nr,nz[,nphi]] cm^-3 Ion density for each thermal species
denn Float64 2/3 [nlevs,nthermal,nr,nz[,nphi]] cm^-3 Cold neutral density
zeff Float64 2/3 [nr,nz[,nphi]] NA Z-effective
vr Float64 2/3 [nr,nz[,nphi]] cm/s Radial component of the bulk plasma rotation/flow
vt Float64 2/3 [nr,nz[,nphi]] cm/s Torodial/Phi component of the bulk plasma rotation/flow
vz Float64 2/3 [nr,nz[,nphi]] cm/s Z component of the bulk plasma rotation/flow
description String 0 NA NA Plasma Parameters
coordinate system String 0 NA NA Cylindrical

and where the fields group has the following datasets

Variable Type Rank Dimensions Units Description
nr Int16 0 NA NA Number of radii
nz Int16 0 NA NA Number of z values
nphi Int16 0 NA NA Number of phi values (Optional)
r Float64 1 [nr] cm Array of radii
z Float64 1 [nz] cm Array of z values
phi Float64 1 [nphi] rad Array of phi values (Optional)
r2d Float64 2/3 [nr,nz[,nphi]] cm 2D/3D array of radii r = r2d(r,z[,phi])
z2d Float64 2/3 [nr,nz[,nphi]] cm 2D/3D array of z values z = z2d(r,z,[phi])
time Float64 0 NA s Time when the fields data were collected/reconstructed
data_source String 0 NA NA Source of the fields data
mask Int16 2/3 [nr,nz[,nphi]] NA Boolean mask that indicates where the fields are well defined
br Float64 2/3 [nr,nz[,nphi]] T Radial component of the magnetic field
bt Float64 2/3 [nr,nz[,nphi]] T Torodial/Phi component of the magnetic field
bz Float64 2/3 [nr,nz[,nphi]] T Z component of the magnetic field
er Float64 2/3 [nr,nz[,nphi]] V/m Radial component of the electric field
et Float64 2/3 [nr,nz[,nphi]] V/m Torodial/Phi component of the electric field
ez Float64 2/3 [nr,nz[,nphi]] V/m Z component of the electric field
description String 0 NA NA Electromagnetic Field
coordinate system String 0 NA NA Cylindrical

Distributions

The fast-ion distribution function typically does not have a functional form. This means that we need to input the fast-ion distribution function into FIDASIM. FIDASIM accepts three different types of fast-ion distributions.

  1. Guiding Center Distribution Function: F(E,p,R,Z[,Phi])
  2. Guiding Center Monte Carlo distribution
  3. Full-orbit Monte Carlo distribution

Supporting different types of distributions greatly facilitates the study of fast-ion transport.

FIDASIM reads the fast-ion distribution from an HDF5 file that has the following variables depending on the distribution type.

Guiding Center Distribution Function: F(E,p,R,Z[,Phi])

Variable Type Rank Dimensions Units Description
type Int16 0 NA NA Distribution type (1)
nr Int16 0 NA NA Number of radii
nz Int16 0 NA NA Number of z values
nphi Int16 0 NA NA Number of phi values (Optional)
r Float64 1 [nr] cm Array of radii
z Float64 1 [nz] cm Array of z values
phi Float64 1 [nphi] cm Array of phi values (Optional)
r2d Float64 2 [nr,nz] cm 2D array of radii r = r2d(r,z)
z2d Float64 2 [nr,nz] cm 2D array of z values z = z2d(r,z)
time Float64 0 NA s Time of the distribution
data_source String 0 NA NA Source of the distribution data
nenergy Int16 0 NA NA Number of energy values
npitch Int16 0 NA NA Number of pitch values
energy Float64 1 [nenergy] keV Energy array
pitch Float64 1 [npitch] NA Pitch array w.r.t magnetic field
denf Float64 3 [nr,nz[,nphi]] cm^-3 Fast-ion density
f Float64 5 [nenergy,npitch,nr,nz[,nphi]] fast-ions/(dE dP cm^3) Fast-ion distribution F(E,p,R,Z[,Phi])

The Guiding Center Distribution Function is a function of Energy, pitch, R, Z and Phi. The distribution can be mapped onto the 2D R-Z grid or 3D cylindrical grid, where the plasma parameters and fields are defined.

Guiding Center Monte Carlo Distribution

Variable Type Rank Dimensions Units Description
type Int16 0 NA NA Distribution type (2)
time Float64 0 NA s Time of the distribution
data_source String 0 NA NA Source of the distribution data
nparticle Int32 0 NA NA Number of MC particles
nclass Int16 0 NA NA Number of orbit classes
class Int16 1 [nparticle] NA Orbit class of the MC particle
weight Float64 1 [nparticle] fast-ions Weight of the MC particle
r Float64 1 [nparticle] cm R positions of the MC particle
z Float64 1 [nparticle] cm Z positions of the MC particle
phi Float64 1 [nparticle] rad Phi positions of the MC particle (Optional)
energy Float64 1 [nparticle] keV Energy of the MC particle
pitch Float64 1 [nparticle] NA Pitch w.r.t the magnetic field of the MC particle

The sum(weight) = # of Fast-ions in phase space sampled by the MC particles.

The class variable can take values in the range of 1:nclass. If there are multiple classes of particles the FIDA signal for each class will be calculated.

Full-orbit Monte Carlo Distribution

Variable Type Rank Dimensions Units Description
type Int16 0 NA NA Distribution type (3)
time Float64 0 NA s Time of the distribution
data_source String 0 NA NA Source of the distribution data
nparticle Int32 0 NA NA Number of MC particles
nclass Int16 0 NA NA Number of orbit classes
class Int16 1 [nparticle] NA Orbit class of the MC particle
weight Float64 1 [nparticle] fast-ions Weight of the MC particle
r Float64 1 [nparticle] cm R positions of the MC particle
z Float64 1 [nparticle] cm Z positions of the MC particle
phi Float64 1 [nparticle] rad Phi positions of the MC particle (Optional)
vr Float64 1 [nparticle] cm/s Radial component of the MC particle velocity
vt Float64 1 [nparticle] cm/s Torodial/Phi component of the MC particle velocity
vz Float64 1 [nparticle] cm/s Z component of the MC particle velocity

The sum(weight) = # of Fast-ions in phase space sampled by the MC particles.

The class variable can take values in the range of 1:nclass. If there are multiple classes of particles the FIDA signal for each class will be calculated.

Relevent Namelist Settings

  • ai: Ion mass [amu]
  • impurity_charge: Impurity charge number 5=Boron, 6=Carbon, ...
  • ab: Fast/Beam-ion mass [amu]
  • equilibrium_file: Equilibrium file location
  • distribution_file: Distribution file location

Fortran References