EMSES-tutorials

EMSES Parameter File: `plasma.inp`

Note: Include the following unit-conversion key directive at the very top of plasma.inp to normalize grid spacing and light speed:

!!key dx=[0.5], to_c=[10000.0]

EMSES Parameter File: plasma.inp

Unit System and Conversion

EMSES uses a normalized unit system to simplify computations and reduce numerical cost. Four primary conversions are fixed:

Grid spacing (dx) [m] → 1
Speed of light (cv) [m/s] → 10000
Vacuum permittivity (epsilon_0) [F/m] → 1
Electron charge-to-mass ratio (q/m) [C/kg] → –1

All other physical quantities scale consistently according to these base units. Conversion formula:

X_EMSES = X_phys × C

where C derives from the chosen normalizations. See the emout conversion module or Excel sheet for explicit coefficients.

Namelist Groups Overview

&esorem: Field solver mode
&jobcon: Job control
&digcon: Diagnostic output control
&plasma: Plasma properties
&tmgrid: Time & spatial grid
&mpi: MPI decomposition
&intp: Particle integration & initialization
&ptcond: Surface/conductor boundary parameters
&gradema: Surface charging acceleration
&dipole: Embedded dipole source
&emissn: Particle emission

Detailed Parameter Reference

\&esorem

Defined in namels.f90.

emflag (integer): 1=full EM, 0=electrostatic

\&jobcon

jobnum(2) (integer): [new/continue, always 1]
nstep (integer): total time steps

\&digcon

Controls diagnostics (HDF5, current, particle, etc.). Key parameters:

hdfdigstart, hdfdigend (integer): start/end step for HDF output
ifdiag, ijdiag (integer): field/current output intervals
ipadig(1:3) (integer): in-situ grid size
ipahdf(1:3), ipaxyz(18), ifxyz(1:7), ijxyz(1:3) (integer arrays): masks and flags
isort, itchck (integer): sorted output, checkpoint interval
ildig, ikdiag, ivdiag, irhsp, imdig (integer): specialized diagnostics

\&plasma

Fundamental plasma parameters (in EMSES units):

wp(1:nspec) (real): plasma frequency per species
wc (real): cyclotron frequency
cv (real): normalized light speed

\&tmgrid

Time & spatial grid:

dt (real): time-step size
nx, ny, nz (integer): grid points
dx (real): grid spacing

\&system

System parameters:

nspec (integer): number of species
nfbnd, npbnd (integer): field/particle boundary (0=periodic, 2=free)
mtd_vbnd (integer): potential BC (0=periodic, 1=Dirichlet, 2=Neumann)
separate_accumulated_and_space_charge (logical): if .true., compute the electric‐field contributions from accumulated charge and from space charge separately. Default is .true.

\&mpi

MPI domain decomposition:

nodes(1:3) (integer): processes along x, y, z

\&intp

Particle integration & initialization:

qm(1:nspec), npin(1:nspec), np(1:nspec) (real/integer arrays): q/m, initial/buffer particle counts
path(1:nspec), peth(1:nspec) (real arrays): thermal velocities
vdri(1:nspec), vdthz(1:nspec), vdthxy(1:nspec) (real arrays): bulk-flow magnitudes & angles

\&ptcond

Surface & conductor boundaries.

Basic Settings

npc, npcg (integer): counts of solid/conductor bodies
pcgs, ccgs (integer arrays): conductor grouping
mtd_vchg (integer): potential treatment (0=float, -1=fixed)
pfixed (real): fixed potential value

Body Geometry

geotype (integer): 0/1=rectangular, 2=cylinder, 3=sphere
bdyalign (integer): cylinder axis (1=x, 2=y, 3=z)
bdyradius, bdyedge, bdycoord (real arrays): shape parameters
{x,y,z}{l,u}pc (real): rectangular bounds

Finbound Extension

(See next section)

\&gradema

grad_coef (real): acceleration coef. for surface charging

\&dipole

Embedded magnetic dipole source:

md (real): dipole field magnitude
mdx, mdy, mdz (integer): grid indices of dipole center
mddir (integer): orientation (1=x, 2=y, 3=z)

\&emissn

Particle emission settings:

nflag_emit(1:nspec) (integer): 0=external, 1=internal, 2=internal (with pe-raycasting)
nepl (integer): # of emission surfaces
curf (real): base current density
curfs(1:nepl) (real): per-surface overrides
nemd(1:nepl) (integer): direction/surface (±1=x, ±2=y, ±3=z)
xmaxe(1:nepl), xmine(1:nepl), ymaxe(1:nepl), ymine(1:nepl), zmaxe(1:nepl), zmine(1:nepl) (integer arrays): emission-region bounds
ipcpl(1:nepl) (integer): Specifies the conductor number (ipc at geotype(ipc)) if this emission surface constitute the conductor object (by deafult 1).
pe_ray_cast (logical): solar-illumination-driven emission flag; Particles with nflag_emit == 2 are emitted from the regions of internal boundaries (as defined by the Finbound extension) that are exposed to sunlight
ray_zenith_angle_deg(1:nspec), ray_azimuth_angle_deg(1:nspec) the angle of sunlight is defined (default: vdthz(1) and vdthxy(1))
periodic_raycast raycast with periodic boundary flag.

Finbound Extension (Additional Parameters)

All following parameters belong to the \&ptcond group and are implemented via the finbound module (see allcom.f90 and particle_collision.f90). They enable precise control over complex inner boundary geometries.

boundary_type (character(30))
- Specifies the overall inner-boundary geometry for one body.
- Supported values:
  - none (no special inner boundary)
  - flat-surface (planar cut)
  - rectangle-hole, cylinder-hole, hyperboloid-hole, ellipsoid-hole (hole through a surface)
  - complex (combined shapes defined by boundary_types)
boundary_types(1:nboundary_types) (character(30) array)
- Specifies the overall inner-boundary geometry for each body.
- Supported values:
  - flat-surface (planar cut)
  - rectangle-hole, cylinder-hole, hyperboloid-hole, ellipsoid-hole (hole through a surface)
  - rectanglex, rectangley, rectanglez (rectangular prism in X/Y/Z)
  - circlex, circley, circlez (cylindrical cut aligned with an axis)
  - cuboid (axis-aligned block)
  - diskx, disky, diskz (flat disk perpendicular to an axis)
  - sphere
boundary_conductor_id(1:nboundary_types)
- Specifies the conductor number (ipc at geotype(ipc)) if this boundary condition constitute the conductor object.

Geometry Parameter Arrays (each dimensioned by nboundary_types):

cylinder_origin(3, nbt)
- Center coordinates [x, y, z] of each cylindrical sub-boundary.
cylinder_radius(nbt)
- Radius of each cylinder.
cylinder_height(nbt)
- Height (extent along axis) of each cylinder.
rectangle_shape(6, nbt)
- Six-element array: (x_lower, x_upper, y_lower, y_upper, z_lower, z_upper), defining each rectangular prism.
cuboid_shape(6, nbt)
- Same format as rectangle_shape, used interchangeably for cuboid bodies.
sphere_origin(3, nbt)
- Center [x, y, z] of each spherical sub-boundary.
sphere_radius(nbt)
- Radius of each sphere.
circle_origin(3, nbt)
- Center [x, y, z] of each circular hole (disk) or cylindrical cut.
circle_radius(nbt)
- Radius of each circular feature.
disk_origin(3, nbt)
- Center [x, y, z] of each flat disk surface.
disk_height(nbt)
- Plane position (thickness) at which each disk lies.
disk_radius(nbt)
- Outer radius of each disk.
disk_inner_radius(nbt)
- Inner radius (hole) of each annular disk.

(Here, nbt denotes nboundary_types.)

Example `plasma.inp`

&esorem
  emflag = 0
&end

&jobcon
  jobnum = 0, 1
  nstep  = 100000
&end

&plasma
  wp = 0.5950738d0, -1.0d0
  wc = 0.0d0
  cv = 10000.0d0
&end

&tmgrid
  dt = 0.01d0
  nx = 128; ny = 128; nz = 128
  dx = 1.0d0
&end

... (continued)

Refer to the EMSES user guide and source-code comments for further configuration details and advanced options.

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