D0FUS

D0FUS (Design 0-dimensional for Fusion Systems) is a comprehensive Python-based tool for tokamak fusion power plant design and analysis. It enables rapid exploration of design space through 0D/1D physics models.

Installation

Requirements

• Python 3.8+
• Dependencies: pip install -r requirements.txt

Recommended

• Spyder IDE for interactive use

Quick Install

# Clone the repository
git clone https://github.com/IRFM/D0FUS.git

# Or make use of the pip version:
pip install d0fus

Project Structure

D0FUS/
├── D0FUS_BIB/                      # Core library modules
│   ├── D0FUS_import.py                 # Common imports
│   ├── D0FUS_parameterization.py       # Physical constants and parameters
│   ├── D0FUS_physical_functions.py     # Plasma physics functions
│   └── D0FUS_radial_build_functions.py # Engineering and radial build
│
├── D0FUS_INPUTS/                   # Input parameter files
│   └── default_input.txt               # Default configuration
│
├── D0FUS_OUTPUTS/                  # Generated outputs (auto-created)
│   ├── Run_D0FUS_YYYYMMDD_HHMMSS/      # Single run results
│   ├── Scan_D0FUS_YYYYMMDD_HHMMSS/     # Scan results with figures
│   └── Genetic_D0FUS_YYYYMMDD_HHMMSS/  # Genetic optimization results
│
├── D0FUS_EXE/                      # Execution modules
│   ├── D0FUS_run.py                    # Single design point calculation
│   ├── D0FUS_scan.py                   # 2D parameter space scan
│   └── D0FUS_genetic.py                # Genetic algorithm optimization
│
├── D0FUS.py                        # Main entry point
├── requirements.txt                # Python dependencies
└── README.md                       # This file

D0FUS Startup

Recommended Execution

Launch Spyder and open D0FUS.py

python D0FUS.py

Execute, you'll then be prompted to select an input file.

Script Integration

You can also import and use D0FUS modules in your own scripts:

from D0FUS_EXE import D0FUS_run

# Run a calculation
results = D0FUS_run.main("D0FUS_INPUTS/my_config.txt")

# Access results
B0, B_CS, Q, Ip, betaN, ... = results

Execution Modes

D0FUS automatically detects the execution mode based on the input file format. Three modes are available:

Mode	Purpose	Input format	Parameters
RUN	Single design point calculation	R0 = 9	Fixed values only
SCAN	2D parameter space exploration	R0 = [3, 9, 25]	Exactly 2 parameters with [min, max, n_points]
OPTIMIZATION	Genetic algorithm cost minimization	R0 = [3, 9]	2+ parameters with [min, max]

RUN mode evaluates a single tokamak configuration and outputs all plasma parameters, magnetic fields, power balance, and radial build dimensions.

SCAN mode generates 2D maps over two parameters, visualizing feasibility regions bounded by plasma stability limits (Greenwald density, Troyon beta, kink safety factor) and engineering constraints.

OPTIMIZATION mode uses a genetic algorithm to find the reactor configuration minimizing cost while satisfying all physics and engineering constraints. The optimizer explores the multi-dimensional parameter space defined by the bounds and evolves the population toward optimal solutions.

Input

Parameter Handling

All parameters have built-in default values. When an input file is provided, only the specified parameters are overwritten while all others retain their defaults. This allows minimal input files containing only the parameters of interest.

For example, an input file with just:

R0 = 7
Bmax = 14

will run D0FUS with these two values modified, using defaults for everything else.

Parameter Reference

Parameter	Description	Unit	Default	Options
Geometry
P_fus	Fusion power	MW	2000
R0	Major radius	m	9
a	Minor radius	m	3
Option_Kappa	Elongation model	-	Wenninger	Stambaugh, Freidberg, Wenninger, Manual
κ_manual	Manual elongation (if Option_Kappa = Manual)	-	1.7
b	Plasma->TF coil distance	m	1.2
Magnetic Field
Bmax	Maximum field on TF coils	T	12
Technology
Supra_choice	Superconductor material	-	Nb3Sn	NbTi, Nb3Sn, REBCO
Radial_build_model	Radial build calculation model	-	D0FUS	D0FUS, Freidberg
Choice_Buck_Wedg	TF coil mechanical configuration	-	Wedging	Plug, Bucking, Wedging
Chosen_Steel	Structural steel grade	-	316L	316L, N50H, JK2LB, Manual
Plasma Physics
Scaling_Law	Energy confinement scaling law	-	IPB98(y,2)	IPB98(y,2), ITPA20, ITPA20-IL, DS03, L-mode, L-mode OK, ITER89-P
H	H-factor (confinement enhancement)	-	1
Tbar	Volume-averaged temperature	keV	14
nu_T	Temperature profile peaking factor	-	1
nu_n	Density profile peaking factor	-	0.1
L_H_Scaling_choice	L-H threshold scaling	-	New_Ip	New_Ip, Martin, New_S
Bootstrap_choice	Bootstrap current model	-	Freidberg	Freidberg, Segal
Operation
Operation_mode	Operating scenario	-	Steady-State	Steady-State, Pulsed
Temps_Plateau_input*	Burn duration (Pulsed mode)	s	7200
P_aux_input*	Auxiliary heating power (Pulsed mode)	MW	100

*Parameters marked with * are only relevant when Operation_mode = Pulsed.

Input File Format

The format of variable parameters determines which execution mode D0FUS will use:

RUN mode — Fixed values only:

R0 = 9

See D0FUS_INPUTS/default_input.txt for a complete example.

SCAN mode — Exactly 2 parameters with [min, max, n_points]:

R0 = [3, 9, 25]
a = [1, 3, 25]

See D0FUS_INPUTS/scan_input_example.txt for a complete example.

OPTIMIZATION mode — 2+ parameters with [min, max]:

R0 = [3, 9]
a = [1, 3]
Bmax = [10, 16]

See D0FUS_INPUTS/input_genetic_example.txt for a complete example.

Genetic Algorithm Settings

For OPTIMIZATION mode, optional algorithm parameters can be added to the input file:

Parameter	Description	Default
population_size	Number of individuals per generation	50
generations	Maximum number of generations	100
crossover_rate	Crossover probability	0.7
mutation_rate	Mutation probability	0.2

Output

RUN Mode Output

Results are saved in timestamped directories:

D0FUS_OUTPUTS/Run_D0FUS_20251106_123456/
├── input_parameters.txt        # Copy of input configuration
└── output_results.txt          # Complete calculation results

Output includes:

• Plasma parameters (Ip, ne, Te, βN, Q, τE)
• Magnetic fields (B0, BCS, Bpol)
• Power balance (Pfus, PCD, Psep, Pthresh)
• Radial build dimensions (TF thickness, CS thickness)

SCAN Mode Output

D0FUS_OUTPUTS/Scan_D0FUS_20251106_123456/
├── scan_parameters.txt         # Scan configuration
└── scan_map_[iso]_[bg].png     # High-resolution figure (300 dpi)

Scan visualizations show:

• Plasma stability boundaries (density, beta, kink safety factor)
• Radial build feasibility limits
• Iso-contours of key parameters (Ip, Q, B0, etc.)

OPTIMIZATION Mode Output

D0FUS_OUTPUTS/Genetic_D0FUS_20251106_123456/
├── optimization_config.txt     # Optimization parameters and bounds
├── optimization_results.txt    # Best solution and convergence history
└── convergence_plot.png        # Fitness evolution over generations

Optimization results include:

• Best individual: optimal parameter values minimizing reactor cost
• Fitness evolution: cost reduction across generations
• Constraint satisfaction: plasma stability (Greenwald, Troyon, kink) and radial build feasibility
• Convergence diagnostics: population diversity and stagnation metrics

Contributing

Contributions are welcome! Please contact us:

• Email: timothe.auclair@cea.fr

License

This project is licensed under the CeCILL-C License, a French free software license compatible with the GNU LGPL.

See the LICENSE file for details.

© 2025 CEA/IRFM

(back to top)