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Prototype of a predictive engineering model (PEM) of a Hall thruster. Integrates sub-models from multiple disciplines to simulate a Hall thruster operating in a vacuum chamber. Uses uncertainty quantification techniques to extrapolate model predictions to a space-like environment.

Installation

We highly recommend using pdm: 

pip install --user pdm
git clone https://github.com/JANUS-Institute/HallThrusterPEM.git
cd HallThrusterPEM
pdm install

Quickstart

import numpy as np
import matplotlib.pyplot as plt

from hallmd.models.pem import pem_v0
from hallmd.data.loader import spt100_data
from hallmd.utils import plot_qoi

system = pem_v0()
system.fit(max_iter=10)

# Show model predictions vs experimental thrust data
data = spt100_data(['T'])[0]
inputs = data['x']  # Pressure, Anode voltage, Anode mass flow rate
Nx, num_samples = inputs.shape[0], 100
xs = np.zeros((Nx, num_samples, len(system.exo_vars)))

for i in range(Nx):
    nominal = dict(PB=inputs[i, 0], Va=inputs[i, 1], mdot_a=inputs[i, 2])
    xs[i, :, :] = system.sample_inputs(num_samples, use_pdf=True, nominal=nominal)

ys = system.predict(xs, qoi_ind='T')*1000       # Predicted thrust [mN]
y = data['y']*1000                              # Experimental thrust [mN]
y_err = 2 * np.sqrt(data['var_y'])*1000         # Experimental noise [mN]

fig, ax = plt.subplots()
pressure = 10 ** data[:, 0]
idx = np.argsort(pressure)
ax.errorbar(pressure, y, yerr=y_err, fmt='or', capsize=3, label='Experiment')
plot_qoi(ax, pressure[idx], ys[idx, :], 'Background pressure (Torr)', 'Thrust (mN)', legend=True)
plt.show()

Viewing the docs

The documentation can be viewed locally with the mkdocs utility: 

cd HallThrusterPEM
pdm run docs         # Open http://127.0.0.1:8000/ in a browser to view
Eventually this will be made public when the project is made open-source.

Project structure

HallThrusterPEM                 # Root project directory
|- docs                         # Documentation and references
|- scripts                      # Scripts for building PEM surrogates
|  |- pem_v0                    # PEM v0 surrogate scripts
|  |  |- gen_data.sh
|  |  |- train_surr.sh
|  |- debug                     # Scripts for debugging SLURM workflow
|  |- analysis                  # Scripts for UQ analysis (Monte Carlo, Sobol, etc.)
|  |- ...
|- src/hallmd                   # Python package source code root
|  |- models                    # Python wrappers for sub-models
|  |  |- thruster.py
|  |  |- ...
|  |- data                      # Experimental data
|  |  |- spt100                 # Contains all data for the SPT-100
|  |  |- ...
|  |  |- loader.py              # Helper functions for loading data
|  |- utils.py                  # Useful utility functions
|  |- juliapkg.json             # Specifies version of Hallthruster.jl
|- tests                        # Testing for models, generating data, and plotting results
|- results                      # Test scripts write data here (but kept out of the repo)
|- pdm.lock                     # Frozen dependencies file
|- setup_env.sh                 # Convenience script for setting up pdm environment

Contributing

See the contribution guidelines.

Citations

Coming soon.