Performant Python functions for calculating electromagnetic radiation from moving charges.
This project is authored by Jonathan Zrake as part of a graduate-level electromagnetic theory course at Clemson University. It can be used as a pedagogical tool to explore radiation from relativistic moving charges, and might have research applications in astrophysics and plasma physics.
Poynting provides tools for computing the electromagnetic field and energy flow (Poynting vector) from charged particles following prescribed trajectories. It combines C++ for performance-critical calculations with a convenient Python interface.
- Calculation of Liénard-Wiechert potentials for moving charges
- Computation of electromagnetic fields via the Faraday tensor
- Evaluation of Poynting vectors (energy flux) at arbitrary points
- Time-averaging of radiation patterns
- High-order finite differencing for improved accuracy
- Relativistic calculations using proper four-vector formalism
from poynting import ParticleTrajectory, poynting_vector, poynting_vector_time_avg
# Create a charged particle oscillating along the z-axis
# with angular frequency omega and amplitude ell (the speed
# of light is normalized to c=1 throughout the project)
particle = ParticleTrajectory(omega=0.9, ell=1.0)
# Calculate the instantaneous Poynting vector at a specific point and time
S = poynting_vector(particle, t=0.5, x=10.0, y=0.0, z=0.0)
print(f"Energy flux: {S.t}, direction: ({S.x}, {S.y}, {S.z})")
# Calculate the time-averaged energy flux in the radial direction
avg_flux = time_averaged_energy_flux(particle, x=10.0, y=0.0, z=5.0)
print(f"Time-averaged radial energy flux: {avg_flux}")This package has not yet been published on PyPI, but you can install it from GitHub using pip:
pip install git+https://github.com/clemson-cal/poynting.gitYou will require a C++ compiler and the CMake build system, because the extension module will be built from source. Wheels may be added in the future.
Poynting implements:
- Fully covariant formulation in C++ backend
- Electromagnetic field tensor is derived from four-potential by numerical finite differencing; 2nd, 4th, and 6th order available
- Numerical root-finding for retarded-time calculation implemented in C++
- Accurate time averaging of energy flux based on high-order Gaussian quadrature
MIT License