TOKAMAK FUSION REACTOR SIMULATION (3D RAYTRACED)

A comprehensive 3D volumetric simulation of a Tokamak nuclear fusion reactor, featuring realistic plasma physics, magnetic confinement, and a high-fidelity ray-traced rendering engine using OpenGL Compute Shaders.

PROGRESS SO FAR:

https://github.com/user-attachments/assets/cf4fcc6d-587e-4783-8f35-de0766aaf0fe

Star History

OVERVIEW

This project simulates the complex behavior of plasma within a tokamak reactor. Originally a 2D cross-sectional simulation, it has been upgraded to a full 3D volumetric experience.

The simulation combines:

1. Plasma Physics Engine: Calculates particle trajectories (Lorentz force), Coulomb collisions, and D-T fusion reactions.
2. Volumetric Raytracing: A custom compute shader (tokamak_raytrace.comp) performs real-time raymarching to render the plasma density, temperature gradients, and the reactor vessel with physically-based shading.
3. Interactive Controls: Full orbit camera control and real-time parameter tuning via ImGui.

PROJECT STRUCTURE

project/
├── CMakeLists.txt              # Build configuration (CMake)
├── main.cpp                    # Application entry, windowing, and main loop
├── tokamak_raytrace.comp       # GLSL Compute Shader for volumetric raytracing
├── camera.h                    # Orbit camera implementation
├── plasma_physics.h            # core physics engine (particle dynamics, fusion)
├── magnetic_field.h            # Magnetic field calculations (toroidal + poloidal)
├── tokamak_geometry.h          # Reactor geometry definition
├── particle.h                  # Particle data structures
├── ray_tracing.cpp             # Host-side raytracing setup and buffer management
├── particle.vert / .frag       # (Legacy) Basic rasterization shaders
├── external/                   # Dependencies (GLFW, GLAD, GLM)
├── imgui-master/               # ImGui library for UI
└── PHYSICS_LECTURE.md          # Comprehensive physics documentation

FEATURES

Physics Simulation

• 3D Magnetic Confinement: Particles follow helical paths along the two magnetic field lines (toroidal and poloidal (calculated)) in a torus.
• Fusion Reactions: Deuterium-Tritium (D-T) fusion producing Alpha particles and Neutrons.
• Thermal Plasma: Maxwellian velocity distribution at 150 million Kelvin.
• Particle Behavior: Coulomb repulsion, Debye shielding, and boundary reflection.

Visual & Rendering

• Volumetric Raytracing: Real-time accumulation of plasma density and emission using raymarching.
• Dynamic Lighting: Plasma glows based on density and temperature; fusion events create bright flashes.
• Reactor Vessel: Physically-based rendering (PBR) of the tokamak interior.
• ImGui Integration: Real-time control over simulation parameters (under development).

Camera & Controls

• Orbit Camera:
  • Rotate: Left Mouse Button + Drag
  • Pan: Right Mouse Button + Drag
  • Zoom: Mouse Scroll Wheel
• Keyboard:
  • ESC: Exit simulation

COMPILATION

The project now uses CMake for building.

Prerequisites

• OpenGL 4.3+ (Required for Compute Shaders)
• CMake 3.20+
• C++17 Compiler (MSVC recommended on Windows)

Build Instructions (Windows)

1. Open the project folder in a terminal.
2. Create a build directory:

   mkdir build
   cd build
   

3. Configure with CMake:

   cmake ..
   

4. Build the project:

   cmake --build . --config Release
   

5. Run the executable:

   ./Release/FusionTokamakSim.exe
   

Note: The current CMake setup supports Windows and Ubuntu. On Linux, dependencies are fetched automatically during CMake configure.

Build Instructions (Ubuntu)

The project can now be built directly on Ubuntu using CMake. Dependencies (GLFW, GLAD, GLM, ImGui) are fetched automatically during configure.

1. Install required system packages:

   sudo apt update
   sudo apt install -y build-essential cmake git pkg-config \
     libx11-dev libxrandr-dev libxinerama-dev libxcursor-dev libxi-dev \
     libwayland-dev libxkbcommon-dev wayland-protocols libegl1-mesa-dev libgl1-mesa-dev
   

2. Configure and build:

   cmake -S . -B build-ubuntu
   cmake --build build-ubuntu -j
   

3. Run:

   ./build-ubuntu/FusionTokamakSim
   

Notes:

• First configure/build requires internet access for dependency download.
• Requires an OpenGL 4.3+ capable GPU/driver for compute shaders.

PHYSICS DOCUMENTATION

See PHYSICS_LECTURE.md for:

• Detailed derivations of magnetic confinement.
• Fusion cross-sections and reaction rates.
• Plasma stability and tokamak geometry.

SCIENTIFIC ACCURACY & LIMITATIONS

This simulation implements:

• ✓ Lorentz force (v × B)
• ✓ D-T Fusion energy release (17.6 MeV)
• ✓ Volumetric plasma density visualization
• ✓ Toroidal confinement geometry

Simplifications:

• The raytracer visualizes a density field derived from particle positions/functions, which is an approximation of the discrete particle data for performance.
• Relativistic effects are ignored.
• Full Magnetohydrodynamics (MHD) fluid simulation is approximated by particle kinetics.

LICENSE

This code is provided for educational and research purposes.

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Note: Rendering volumetric plasma is GPU-intensive. If you experience low framerates, try reducing the window size or adjusting the raymarching step size in tokamak_raytrace.comp.