Built-in Presets

Detailed explanation of all 10 simulation presets.

Overview

Each preset is a pre-configured scenario demonstrating different physics phenomena. Load via ImGui “Presets” dropdown or set PRESET in config.py:

PRESET = "lhc_pp"  # or "default", "rutherford", etc.

Preset Listing

1. Default Preset

Purpose: Exploration mode with random particles

Configuration:

  • Particles: 20 random types

  • Forces: Coulomb (K=40), Gravity (G=6)

  • Fields: None

  • Boundary: Reflection

  • Initial region: Sphere ±5 units

Use case:

  • Getting familiar with the UI

  • Free experimentation

  • Sandbox for custom parameter tuning

Initial appearance:

  • Random cloud of colored spheres

  • Gentle Coulomb repulsion spreads them

  • Some may be attracted by gravity

2. Rutherford Preset

Purpose: Coulomb scattering (Rutherford scattering experiment)

Configuration:

  • Particles: 1 stationary target (nucleus, high mass/charge)

  • Incoming beam: 30 alpha particles (helium nuclei) from edge

  • Forces: Coulomb repulsion (K=80, very strong)

  • Boundary: Reflection

  • Initial geometry: Beam aimed horizontally at center

Physics demonstrated:

  • Coulomb repulsion at short range

  • Scattering angle vs impact parameter

  • Hyperbolic trajectories in inverse-square potential

Observation:

  • Direct hits scatter backward (large angle)

  • Grazing hits scatter slightly forward

  • Distribution follows Rutherford formula

3. Cyclotron Preset

Purpose: Charged particle motion in magnetic field

Configuration:

  • Particles: 15 random charged particles

  • Magnetic field: B = (0, 0, 3) [strong uniform field in z-direction]

  • Forces: Lorentz force only

  • Boundary: Reflection

  • Initial velocity: in xy-plane

Physics demonstrated:

  • Circular motion (cyclotron radius)

  • Frequency independent of velocity (cyclotron frequency ω = qB/m)

  • Different masses → different orbit radii at same speed

Observation:

  • Particles spiral and circle

  • Heavy particles (protons) have larger orbits than light (electrons)

  • Synchrotron radiation (if enabled) causes spiral decay

4. LHC pp Preset

Purpose: Proton-proton high-energy collisions (LHC-style physics)

Configuration:

  • Particles: Two beams of 25 protons each

  • Beams: Counter-rotating at high speed (v ≈ 0.9c in simulation units)

  • Forces: Strong nuclear force (K_s=50), Coulomb (K=40)

  • Collision energy: ~high-mass pair creation possible

  • Decay products: Pions, kaons, muons

Physics demonstrated:

  • Head-on and glancing collisions

  • High-energy annihilation → meson/hadron production

  • Pair creation (e.g., e⁺ + e⁻ from initial energy)

  • Color-charge (QCD) interactions

Observation:

  • Violent particle showers on collision

  • Trail explosions when protons meet

  • Short-lived decay products

Warning: Very CPU-intensive; 60+ particles may cause FPS drop

5. e⁺e⁻ Annihilation Preset

Purpose: Electron-positron pair annihilation (LEP/ILC physics)

Configuration:

  • Particles: 20 electrons + 20 positrons

  • Beams: Head-on approach at high speed

  • Forces: Coulomb attraction/repulsion, no gravity

  • Pair creation: Enabled (high energy)

  • Decay products: Photons, muon pairs, hadron jets

Physics demonstrated:

  • Annihilation of matter + antimatter

  • Conversion to energy (via photons, bosons)

  • Creation of new particle pairs from energy

  • CP-violation signatures (if any)

Observation:

  • Electrons and positrons spiral toward each other

  • On collision, massive energy release → photons/muons

  • Fireworks-like particle cascade

6. Black Hole Preset

Purpose: Particle dynamics around a black hole

Configuration:

  • Central mass: Supermassive black hole (M ≈ 1e9 solar masses in sim units)

  • Schwarzschild radius: r_s ≈ 0.7

  • Accretion disk: Visible orange ring

  • Photon ring: Glowing halo (gravitational lensing)

  • Particles: 15 escaping and in-falling orbits

  • Forces: BH pseudo-Schwarzschild gravity, no other forces

Physics demonstrated:

  • Orbital mechanics near massive object

  • Time dilation near event horizon

  • Gravitational lensing (stars distort behind BH)

  • Accretion dynamics

Observation:

  • Some particles escape parabolically

  • Others settle into elliptical orbits

  • Few plunge into Black Hole (removed from sim)

  • Lensing causes starfield distortion

7. Gas Preset

Purpose: Low-energy thermal gas (Brownian motion, kinetic theory)

Configuration:

  • Particles: 40 random types at low speed (thermal velocity)

  • Forces: Coulomb (K=0.1, weak), Gravity (G=1)

  • Temperature-like: Uniform velocity distribution, ~1 unit/s

  • Boundary: Periodic (toroidal wrapping)

Physics demonstrated:

  • Particle collisions in dense medium

  • Equipartition of energy

  • Diffusion and mixing

  • No long-range order (unlike plasma)

Observation:

  • Particles move slowly, colliding frequently

  • Temperature/energy bars show energy distribution

  • Steady kinetic energy over time

8. Two-Beam Preset

Purpose: Counter-rotating beam collision (asymmetric)

Configuration:

  • Particles: Beam 1 (15 electrons), Beam 2 (15 positrons)

  • Geometry: Beams approach from opposite sides

  • Speed: ~0.8c (moderate relativistic)

  • Forces: Coulomb only

  • Collision zone: Center of domain

Physics demonstrated:

  • Asymmetric vs symmetric collisions

  • Beam dynamics and focusing

  • Electrostatic repulsion between like-charges

Observation:

  • Two organized streams approach

  • Repulsion near center (same-sign charges in region)

  • Some scatter, some pass through

9. Playground Preset

Purpose: Interactive sandbox with wide parameter ranges

Configuration:

  • Particles: Empty initially (use +/- to spawn)

  • All forces: Enabled and accessible via ImGui sliders

  • Boundary: Reflection

  • No pre-set velocities: Particles spawn at rest

Use case:

  • Custom experiments

  • Parameter sensitivity studies

  • Building custom scenarios

Workflow:

  1. Spawn particles: +/+ keys or ImGui slider

  2. Adjust forces in real-time

  3. Observe effects immediately

10. N-Body Virial Preset

Purpose: Self-gravitating particle cluster (cosmology simulation)

Configuration:

  • Particles: 50 random particles (various masses)

  • Forces: Gravity only (G=8), no Coulomb

  • Initial condition: Kinetic energy = 0.5 × |Potential energy| (virial balance)

  • Boundary: None (open space)

  • Geometry: Random sphere, velocity-dispersion model

Physics demonstrated:

  • N-body gravity simulation

  • Virial theorem (E_kin + E_pot = constant… approximately)

  • Dynamic equilibrium and orbit crossing

  • Particle escapers vs bound core

Observation:

  • Cluster oscillates and reforms

  • Some particles escape to infinity

  • Core particles form tighter, bound orbits

  • Long relaxation timescales

Preset Comparison Table

Preset

Particles

Coulomb

Gravity

Magnetic

Strong

Best for

Default

20

Yes (K=40)

Yes (G=6)

No

No

Exploration

Rutherford

30+1

Yes (K=80)

No

No

No

Scattering demo

Cyclotron

15

No

No

Yes (B=3)

No

Magnetism demo

LHC pp

50+

Yes (K=40)

No

No

Yes (K=50)

High-energy collisions

e⁺e⁻

40+

Yes (K=20)

No

No

No

Annihilation demo

Black Hole

15

No

Yes (BH only)

No

No

GR effects

Gas

40

Yes (K=0.1)

Yes (G=1)

No

No

Kinetic theory

Two-Beam

30

Yes (K=40)

No

No

No

Beam dynamics

Playground

0

Yes (tunable)

Yes (tunable)

Yes (tunable)

Yes (tunable)

Custom scenarios

N-Body Virial

50

No

Yes (G=8)

No

No

Cosmology

Creating Custom Presets

To add a custom preset, edit config.py:

# In config.py, add a new preset dict:
PRESETS = {
    "my_preset": {
        "preset_name": "My Custom Experiment",
        "initial_particles": 25,
        "coulomb_k": 50.0,
        "gravity_g": 1.0,
        "magnetic_field": (0, 0, 2),
        # ... other parameters
    }
}

Then in __main__.py, list your preset in the dropdown, and the UI will load it automatically.

See Development for more details on extending the simulation.