Skip to content

VULCAN Quick Start

Run your first photochemical simulation!

1. Run the default demo

From the main VULCAN directory:

python vulcan.py

This will:

  • Generate chemical functions from the reaction network
  • Initialize an Earth-like atmosphere
  • Run the simulation with real-time plotting
  • Complete in ~10-15 minutes

Check the results in output/: 

ls output/

2. Modify the configuration

Edit config.py to change simulation parameters:

Weaker vertical mixing: 

const_Kzz = 1.E7

Carbon-rich atmosphere (C/O = 1): 

C_H = 6.0618E-4

Disable plotting (faster): 

use_live_plot = False

Then run again: 

python vulcan.py

3. Try planet examples

VULCAN includes examples for different planets, listed in cgf_examples.

Available examples:

  • cfg_Earth.txt - Earth
  • cfg_HD189.txt - HD 189733b (hot Jupiter)
  • cfg_HD209.txt - HD 209458b (hot Jupiter)
  • cfg_Jupiter.txt - Jupiter

To try one of these examples, update config.py with the parameters as listed in the example .txt files.

4. Plot results

Run plot_vulcan.py within tools:

python plot_vulcan.py [vulcan output] [species] [plot name] [-h (for plotting height)]

5. Speed tips

Skip regenerating chemistry if you only changed config.py: 

python vulcan.py -n

Only use -n if you haven't modified the reaction network!

Troubleshooting

FastChem not found: 

cd fastchem_vulcan && make && cd ..

Missing Python modules: 

pip install -e .

Simulation too slow: 

# In config.py:
use_live_plot = False
n_layer = 100  # Reduce resolution