Parameters

Jaxion allows the user to configure the simulation via the following set of parameters:

{
  "physics": {
    "quantum": { 
      "default": true,
      "description": "switch on for fuzzy dark matter."
    },
    "gravity": { 
      "default": true,
      "description": "switch on for self-gravity."
    },
    "hydro": { 
      "default": false,
      "description": "switch on for hydrodynamics (isothermal)."
    },
    "particles": { 
      "default": false,
      "description": "switch on for particle-mesh particles."
    },
    "cosmology": { 
      "default": false,
      "description": "switch on for cosmological factors/comoving units."
    },
    "external_potential": { 
      "default": false,
      "description": "switch on for external gravitational potential."
    }
  },
  "domain": {
    "box_size": { 
      "default": 10.0,
      "description": "periodic domain box size [kpc]."
    },
    "resolution_base": { 
      "default": 32,
      "description": "base resolution per linear dimension."
    },
    "resolution_multiplier": {
      "default": 1,
      "description": "resolution multiplier."
    },
    "aspect_ratio": {
      "default": 1,
      "description": "elongation of the domain in the x direction."
    }
  },
  "time": {
    "start": { 
      "default": 0.0,
      "description": "simulation start time [kpc/(km/s)] or [redshift] (cosmology=true)."
    },
    "end": { 
      "default": 1.0,
      "description": "simulation end time [kpc/(km/s)] or [redshift] (cosmology=true)."
    },
    "safety_factor": { 
      "default": 1.0,
      "description": "safety factor for time stepping."
    },
    "adaptive": { 
      "default": false,
      "description": "switch on for adaptive time stepping."
    }
  },
  "output": {
    "path": {
      "default": "./checkpoints",
      "description": "path to output directory."
    },
    "num_checkpoints": {
      "default": 100,
      "description": "number of checkpoints to save."
    },
    "save": {
      "default": true,
      "description": "switch on to save checkpoints."
    },
    "plot_dynamic_range": {
      "default": 100.0,
      "description": "dynamic range for plotting."
    }
  },
  "quantum": {
    "m_22": { 
      "default": 1.0,
      "description": "axion mass [10^{-22} eV]."
    },
    "f_15": { 
      "default": 0.0,
      "description": "self-interaction strength [10^{15} GeV]."
    }
  },
  "hydro": {
    "sound_speed": { 
      "default": 1.0,
      "description": "isothermal sound speed [km/s]."
    }
  },
  "particles": {
    "num_particles": {
      "default": 0,
      "description": "number of particles."
    },
    "particle_mass": {
      "default": 1.0,
      "description": "particle mass [M_sun]."
    },
    "accrete_gas": {
      "default": false,
      "description": "switch on to accrete gas."
    }
  },
  "cosmology": {
    "omega_matter": {
      "default": 0.3,
      "description": "matter density parameter."
    },
    "omega_lambda": {
      "default": 0.7,
      "description": "dark energy density parameter."
    },
    "little_h": {
      "default": 0.7,
      "description": "Hubble parameter little h (H_0 = 100 h km/s/Mpc)."
    }
  },
  "version": {
    "default": "unknown",
    "description": "jaxion version used (auto detected)."
  }
}