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Input and Control
budjensen edited this page Jan 16, 2024
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There are 8 required input files, which each control a different aspect of the simulation. Below is a brief description of each file, as well as a sample input file. Input files must exactly match these samples (or if this wiki is not fully up-to-date, the sample input files within the input_base directory) and be named accordingly.
This module controls the initial state of the system. One can specify the left wall boundary condition (the right wall is grounded), biases, frequency, simulation length, ion species, and cell size and time step. Additional options for saving simulation checkpoints and beginning the simulation from a checkpoint or parabolic electron/ion density profile are found at the bottom of the file.
Click to expand the sample ssc_initial.dat input file
=========================== SYSTEM CONFIGURATION ============================
------------- BC: Left wall potential is ------------------------------------
-- 0 = fixed, or connected to RF if the next option is on --
-- 1 = floating --
-- 2 = connected to external circuit --
-- 3 = Electrode current is specified --
-------d----- 4 = RF potential applied directly or with dielectric layer ----
0
-------d----- Left wall is RF biased (1/0=Yes/No) ---------------------------
1
--dddddd.ddd- Resistor in the external circuit (ohm) ------------------------
10.000
--dddddd.ddd- Electrode area (cm^2) -----------------------------------------
400.000
--dddddd.ddd- External z-electric field parallel to walls (V/m) -------------
0.000
--dddddd.ddd- Left wall potential/battery voltage (V) -----------------------
0.000
--#d.dddE#dd- Left wall RF frequency (Hz) -----------------------------------
1.356E+7
--dddddd.ddd- Left wall RF amplitude (V) ------------------------------------
450.000
--#d.dddE#dd- Left wall RF start time (s) -----------------------------------
0.000E-9
--dddddd.dddd-Plasma layer width (m, beam wavelengths if negative) ----------
0.0670
--dddddd.ddd- Ion mass (a.m.u., m_e if negative) ----------------------------
4.017
--dddddd.ddd- Ion temperature (eV) ------------------------------------------
0.026
======================= PARAMETERS DEFINING SCALE VALUES ====================
--#d.dddE#dd- Plasma density (m^-3) -----------------------------------------
2.560E+14
--dddddd.ddd- Electron temperature (eV) -------------------------------------
2.585
--dddddd----- Number of macroparticles per cell -----------------------------
512
------------- Number of cells per Debye length, micron_flag -----------------
-- If micron_flag = 0: delta_x found from scaling parameters ---
-- If micron_flag > 0: delta_x [mkm] = N_cells * 10^(n-1) ------
--dddddd-#d-- If micron_flag < 0: delta_x [mkm] = N_cells * 10^(n) --------
523 1
------------- Maximal expected velocity (in V_therm_e), picosec_flag --------
-- If picosec_flag = 0: delta_t found from scaling parameters --
-- If picosec_flag > 0: delta_t [ps] = Max_vel * 10^(n-1) ------
--dddddd-#d-- If picosec_flag < 0: delta_t [ps] = Max_vel * 10^(n) --------
18 1
--dddddd----- Number of velocity boxes per unit of V_therm ------------------
128
============================ SIMULATION CONTROL =============================
-------d----- Initial particle density profile (0/1=Uniform/Parabolic) ------
0
--dddddd.ddd- Duration of simulation (ns) -----------------------------------
94395.280
--dddddddd--- Step for saving checkpoints (timesteps, skip if <=0) ----------
-409600
--dddddd----- Seed for random numbers generator -----------------------------
713287
------------- Method of initialization --------------------------------------
-- 0 = start a new run, ordinary --
-- 1 = continue the old run, start at the last checkpoint --
-------d----- 2 = start a new run, take particles from the checkpoint -------
0
2. Data (Diagnostic and Snapshot) Collection Control - ssc_diagnostics.dat
This module contains timing controls for setting up diagnostic output intervals and snapshot capture moments. The bottom of the file contains options for distribution function capture within snapshots.
Click to expand the sample ssc_diagnostics.dat input file
===================== TIME DEPENDENCIES CREATION CONTROL ====================
------------- Diagnostic output interval, t_flag ----------------------------
-- If t_flag <= 0: t_output * 10^(t_flag) in RF periods --------
-- If t_flag > 1: t_output > 0 given in timesteps -------------
--dddddd-#d-- t_output < 0 given in plasma periods --------
128 1
------------- Diagnostic collection start, t_flag ---------------------------
-- If t_flag <= 0: t_start * 10^(t_flag) in RF periods ---------
-- If t_flag > 1: t_start > 0 given in timesteps --------------
--dddddd-#d-- t_start < 0 given in plasma periods ---------
0 1
------------- Diagnostic average window, t_flag - (NOTE: t_avg <= t_output) -
-- If t_flag <= 0: t_avg * 10^(t_flag) in RF periods -----------
-- If t_flag > 1: t_avg > 0 given in timesteps ----------------
--dddddd-#d-- t_avg < 0 given in plasma periods -----------
128 1
--dddddd----- Skip periods of averaging between text outputs (>=0) ----------
10
-----ddd----- Number of probes ( no probes if <= 0 ) ------------------------
0
--dddddd.ddd- Probe coordinates (node number if>0 or millimeters if<0) ------
======================== SNAPSHOTS CREATION CONTROL =========================
------dd----- Number of groups of snapshots ( >= 0 )-------------------------
1
----------- start (ns) ---------- finish (ns) ---------- number -------------
------------dddddd.ddd------------dddddd.ddd--------------dddd---------------
82595.870 92035.398 4
====================== PHASE PLANES CREATION CONTROL ========================
-------d----- Create phase planes ? (1/0) -----------------------------------
0
-ddd-ddd-ddd-ddd--- Number of particles to skip (bulk/left/right/ion, >=0) --
50 0 0 50
============= VELOCITY DISTRIBUTION FUNCTIONS CREATION CONTROL ==============
--dddddd.ddd- Maximal x-velocity for e-v_x-distribution (in V_therm_e) ------
10.000
--dddddd.ddd- Maximal y,z-velocity for e-v_y,z-distribution (in V_therm_e) --
10.000
------dd----- Number of breakpoints (no evdfs if<0, all system used if 0) ---
0
--dddddd.ddd- Breakpoints (ascend., node number if>0 or millimeters if <0) --
============== ENERGY DISTRIBUTION FUNCTIONS CREATION CONTROL ===============
--dddddd.ddd- Maximal energy for electron e-distribution (in eV) ------------
80.000
--dddddd.ddd- Maximal energy for ion e-distribution (in eV) -----------------
20.000
------dd----- Number of breakpoints (no edfs if<0, all system used if 0) ----
3
--dddddd.ddd- Breakpoints (ascend., node number if>0 or millimeters if <0) --
-70.000
-90.000
-110.000
--dddddd.ddd- Maximal energy for ion wall e-distribution (in eV) ------------
120.000
-----ddd----- Number of bins for e-distributions (>0) -----------------------
150
====================== DISTRIBUTION FUNCTION SWITCHES =======================
--d--d--d--d- Velocity ( e-vx, e-vy, e-vz, i-vx, | 1/0 = on/off ) -----------
1 1 1 1
--d--d--d--d- Energy ( e, i, i l-wall, i r-wall | 1/0 = on/off ) ------------
1 1 1 1
This module contains controls for electron-neutral and ion-neutral Monte Carlo collision processes. Options for the background neutral gas density and temperature are found at the top of the file. The collisional model of choice should be chosen at the bottom of the file. Currently the collisional model used in the Turner benchmark and the model default to EDIPIC are included.
For electrons, the collision options that can be turned on/off are:
- Elastic
- Excitation (rfEDIPIC currently ships with the ability for two different excitation collisions)
- Ionization.
For each electron-neutral collision type turned ON a corresponding cross section input table must be provided (named according to ssc_crsect_en_elast.dat, ssc_crsect_en_excit.dat, etc.). The options for ion-neutral collisions are:
- Elastic
- Charge exchange
and use built-in cross sections.
Additional options for electron/ion and turbulence "collision" processes were used for a paper at one point years ago... As such, these turbulence interactions are not used in RF processing plasma simulations.
Click to expand the sample ssc_partcolls.dat input file
================= NEUTRAL COMPONENT PARAMETERS ====================
-------d----- Neutral gas species ( 1 = Argon, 0 = Helium ) -------
0
--dddddd.ddd- Mass (a.m.u.) ---------------------------------------
4.017
--#d.dddE#dd- Density (m^-3) --------------------------------------
9.640e+20 [5 mTorr] 3.219e+21 [100 mTorr] 6.438e+21 [200 mTorr at 300 K]
--dddddd.ddd- Temperature (eV) ------------------------------------
0.026
============ ELECTRON - NEUTRAL COLLISIONS, ACTIVATION ============
-------d----- Elastic-1 (1 = yes, 0 = no) -------------------------
1
-------d----- Excitation-1 (1 = yes, 0 = no) ----------------------
1
-------d----- Excitation-2 (1 = yes, 0 = no) ----------------------
1
-------d----- Ionization-1 (1 = yes, 0 = no) ----------------------
1
============== ELECTRON - NEUTRAL COLLISIONS, CONTROL =============
--dddddd.ddd- Maximal electron energy (eV), default if negative ---
1000.000
--dddddd----- Number of energy values (>0) ------------------------
20001
========== ELECTRON - TURBULENCE, ACTIVATION and CONTROL ==========
-------d----- Turbulence-1 (1 = yes, 0 = no) ----------------------
0
--#d.dddE#dd- Frequency, model-1 (s^-1) ---------------------------
0.146E+07
============== ION - NEUTRAL COLLISIONS, ACTIVATION ===============
-------d----- Elastic-1 (1 = yes, 0 = no) -------------------------
1
-------d----- Charge exchange-1 (1 = yes, 0 = no) -----------------
1
================ ION - NEUTRAL COLLISIONS, CONTROL ================
--dddddd.ddd- Maximal ion energy (eV), default if negative --------
200.000
--dddddd----- Number of energy values (>0) ------------------------
20001
============ ION - TURBULENCE, ACTIVATION and CONTROL =============
-------d----- Turbulence-1 (1 = yes, 0 = no) ----------------------
0
--#d.dddE#dd- Frequency, model-1 (s^-1) ---------------------------
0.000E+00
==== Turner Benchmark Collision Model, ACTIVATION and CONTROL =====
-------d----- Turner Collision Model (1 = yes, 0 = no)-------------
1
This module contains options for assigning temperature anisotropy and drift velocity to the initial electron velocity distribution, and instructions for initial distribution sampling and particle weighting.
Click to expand the sample ssc_anisotropy.dat input file
============== Parameters of anisotropic electron distribution ==============
--dddddd.ddd- X-temperature (eV) --------------------------------------------
2.585
--dddddd.ddd- Z-temperature (eV) --------------------------------------------
2.585
------dd----- Maximal velocity for initial distribution (in V_therm_e) ------
4
--#d.dddE#dd- Plasma density (m^-3), does not affect scaling ----------------
2.560E+14
=============== To calculate the drift velocity one must set: ===============
--dddddd.ddd- E_z (V/m), not to be used in the equation of motion -----------
0.000
--dddddd.ddd- B_x (Gauss), not to be used in the equation of motion ---------
0.000
This module controls particles interactions with simulation boundaries. For electrons, the following options are presented:
- Elastic reflection
- Inelastic backscattering
- Secondary electron emission
and for ions:
- Adsorption
- Reflection
- Adsorption with ion-induced secondary electron emission.
Click to expand the sample ssc_secondary.dat input file
**************************** LEFT PLASMA BOUNDARY ***************************
--- Refluxing of both electrons and ions: ---
--- 0 = off, solid wall ---
--- 1 = thermalization with bulk Te and Ti ---
-------d----- 2 = specular reflection ---------------------------------------
0
--- Additional injection of electron-ion pairs (requires 1 or 2 above): ---
--- 0 = off ---
--- 1 = additional flux equals to ion flux to the right wall ---
-------d----- 2 = constant (Maxwellian source with Te and Ti of the bulk) ---
0
***************************** ELASTIC REFLECTION ****************************
--- Select the model: ---
--- 0 = turned off ---
--- 1 = constant, nonzero for E_min < energy < E_max ---
-------d----- 2 = function 1-1 of incident electron energy ------------------
0
================== ELASTIC REFLECTION, TYPE OF REFLECTION ===================
--- Select the type: ---
--- 0 = specular ---
-------d----- 1 = random ---
1
====================== ELASTIC, MODEL 1, PARAMETERS =========================
-------d.ddd- Value of the coefficient (from 0 to 1) ------------------------
1.000
--dddddd.ddd- LOWER energy boundary E_min, [eV] -----------------------------
0.000
--dddddd.ddd- UPPER energy boundary E_max, [eV] -----------------------------
10000.000
====================== ELASTIC, MODEL 2, PARAMETERS =========================
--dddddd.ddd- Threshold energy, [eV] ----------------------------------------
2.000
--dddddd.ddd- Maximal yield energy, [eV] ------------------------------------
10.000
-------d.ddd- Maximal yield at low energies, [eV] ---------------------------
0.550
--dddddd.ddd- Half-width of decaying part after the maximum, [eV] -----------
14.000
-------d.ddd- Yield, high energy (fraction of total yield, 0 if not used) ---
0.030
*************************** INELASTIC BACKSCATTERING ************************
--- Select the model: ---
--- 0 = turned off ---
--- 1 = constant, nonzero for E_min < energy < E_max ---
-------d----- 2 = function 2-1 of incident electron energy ------------------
0
====================== INELASTIC, MODEL 1, PARAMETERS =======================
-------d.ddd- Value of the coefficient (from 0 to 1) ------------------------
1.000
--dddddd.ddd- LOWER energy boundary E_min, [eV] -----------------------------
0.000
--dddddd.ddd- UPPER energy boundary E_max, [eV] -----------------------------
10000.000
====================== INELASTIC, MODEL 2, PARAMETERS =======================
-------d.ddd- Yield (fraction of total yield, 0 if not used) ----------------
0.070
************************** TRUE SECONDARY EMISSION **************************
--- Select the model: ---
--- 0 = turned off ---
--- 1 = constant, nonzero for E_min < energy < E_max ---
-------d----- 2 = function 3-1 of incident electron energy ------------------
0
================= TRUE SECONDARY, MODEL 1, PARAMETERS =======================
-------d.ddd- Value of the coefficient --------------------------------------
0.300
--dddddd.ddd- LOWER energy boundary E_min, [eV] -----------------------------
4.000
--dddddd.ddd- UPPER energy boundary E_max, [eV] -----------------------------
10000.000
============= TRUE SECONDARY, MODEL 2 (AND CLASSIC), PARAMETERS =============
--dddddd.ddd- Threshold energy, [eV] ----------------------------------------
12.000
--dddddd.ddd- Maximal emission energy, [eV] ---------------------------------
350.000
------dd.ddd- Maximal emission coefficient (normal to the surface) ----------
1.200
-------d.ddd- Smoothness factor (0 = very rough, 2 = polished) --------------
1.000
============= PARAMETERS OF INJECTED TRUE SECONDARY ELECTRONS ===============
--dddddd.ddd- Temperature, [eV] ---------------------------------------------
2.000
**************************** INTERACTION OF IONS ****************************
--- Select the model: ---
--- 0 = 100% adsorption ---
--- 1 = 100% specular reflection ---
-------d----- 2 = 100% ion adsorption, secondary electrons may be emitted ---
0
************************ ION-INDUCED SECONDARY ELECTRON EMISSION ************
-------d.ddd- Value of the coefficient (<1) ---------------------------------
0.200
--dddddd.ddd- Minimal ion energy to start the emission, [eV] ----------------
0.000
--dddddd.ddd- Temperature of injected secondary electron, [eV] --------------
2.000
This module controls electron injection at the boundaries. In a full-device RF plasma simulation, it will not be used.
Click to expand the sample ssc_einject.dat input file
****************** LEFT WALL, CONSTANT ELECTRON INJECTION *******************
--- 0 = turned off ---
--- 1 = monoenergetic beam ---
-------d----- 2 = warm maxwellian source ------------------------------------
0
--dddddd.ddd- Start injection at this moment, [ns] (timesteps if < 0) -------
20.000
====================== ELECTRON INJECTION, PARAMETERS =======================
--dddddd.ddd- Energy (cold) / Temperature (warm), [eV] ----------------------
1.000
--dddddd.ddd- Injection current [A/m^2] -------------------------------------
0.000
****************** RIGHT WALL, CONSTANT ELECTRON INJECTION ******************
--- 0 = turned off ---
--- 1 = monoenergetic beam ---
-------d----- 2 = warm maxwellian source ------------------------------------
0
--dddddd.ddd- Start injection at this moment, [ns] (timesteps if < 0) -------
10.000
====================== ELECTRON INJECTION, PARAMETERS =======================
--dddddd.ddd- Energy (cold) / Temperature (warm), [eV] ----------------------
1.000
--dddddd.ddd- Injection current [A/m^2] -------------------------------------
1.000 1000.000
******************************* SMART TAGS **********************************
--- 0 = turned off (changing velocity sign does not change tag) ---
-------d----- 1 = turned on -------------------------------------------------
0 1
This module controls Langevin coulomb collisions between electrons and electrons and electrons and ions. This module is generally unused for RF processing plasma simulations.
Click to expand the sample ssc_langevin.dat input file
======================== COULOMB COLLISIONS CONTROL =========================
-------d--- Langevin model {off / e-e / e-e and e-i} = {0/1/2} --------------
0
----dddd--- Number of timesteps to skip between e-e collisions (>=0) --------
64
----dddd--- Number of additional cells to calculate Langevin coeffs (>=0) ---
10
------dd--- Maximal velocity for EVDF (in units of scale thermal velocity) --
10
This module controls the x-periodicity of simulation boundaries and allows for simulation of an electron beam plasma, if desired. This module, with the exception of ensuring that we are not simulating a periodic domain, is rarely used in RF processing plasma simulations.
Click to expand the sample ssc_ebeam.dat input file
********************** PERIODICITY OF PARTICLES MOTION **********************
--- 0 = turned off ---
-------d----- 1 = turned on -------------------------------------------------
0
****************************** BEAM IN PLASMA *******************************
--- 0 = turned off ---
--- 1 = monoenergetic beam ---
-------d----- 2 = warm beam -------------------------------------------------
0
--dddddd.ddd- Beam appears at this moment, [ns] (timesteps if < 0) ----------
-1.000
============================= BEAM PARAMETERS ===============================
--dddddd.ddd- Energy, [eV] --------------------------------------------------
40.000
--dddddd.ddd- Temperature (for warm beams only), [eV] ----------------------
4.000
------d.dddd- Relative density (0 < alfa < 1) -------------------------------
0.0010