Aperture is a Particle-in-Cell (PIC) simulation code. The name is a recursive acronym: Aperture simulates Particles, Electrodynamics, and Radiative Transfer at Ultra-Relativistic Energies. It utilizes CUDA/ROCm and runs on Nvidia/AMD GPUs, scaling well up to thousands of nodes on the GPU-based supercomputer Summit. It has been used to study the magnetospheres of pulsars, magnetars, and black holes.

Pulsar Magnetospheres

I'm extremely interested in the physics of compact Astrophysical objects, including neutron stars and black holes. I have studied extensively the magnetospheres of pulsars, which are rapidly rotating neutron stars.

Recently the NICER team produced the most detailed map of hot spots on the surface of the pulsar PSR J0030+0451, and we used this information to infer its magnetic field configuration and obtained its multi-wavelength light curves that agree well with observations.

The left picture shows the magnetic field configuration of PSR J0030+0451. Closed magnetic field lines are drawn in green, and open field lines in light blue. Its current sheet is shown in volume rendering.

Interactive Visualization

I work on interactive visualizations using the framework THREE.js. Modern browsers can directly talk to the GPU, and can render 3D scenes very responsively. These webpages can showcase 3D simulation results, or allow the user to interactively explore parameter spaces of a given physics model.

The picture to the right is an interactive visualization of the Rotating Vector Model (RVM) which aims at describing the polarization of the pulsed radiation from a rotating neutron star. Originally designed to describe the polarization swing of radio signals, the RVM was recently used to fit the polarization swing of X-rays from a magnetar as well.