42 citations · 52 across the 9 of their papers we have counts for
9 papers
Resonant Inverse Compton Scattering and Hard X-ray Emission in Magnetar Magnetospheres
Kun Hu, Nicholas Rackers, Alexander Y. Chen
Magnetars are a subclass of neutron stars with ultra-strong surface magnetic fields. Some magnetars exhibit persistent hard X-ray emission, characterized by power-law tails with ph…
Collisionless Accretion of Finite-Angular-Momentum Plasma onto a Spinning Black Hole
John M. Mehlhaff, Alexander Y. Chen, Martin Luepker +1
In low-luminosity active galactic nuclei like M87* and Sgr A*, the accretion disk around the central supermassive black hole is tenuous and collisionless. As a result, the usual id…
Stable Collisionless Tori Around Kerr Black Holes
Martin Luepker, Yajie Yuan, Alexander Y. Chen
In low-luminosity active galactic nuclei like M87 and Sgr A, the accretion flow in the vicinity of the black hole is in the collisionless regime, meaning that the col…
Global Kinetic Simulations of Monster Shocks and Their Emission
Dominic Bernardi, Yajie Yuan, Alexander Y. Chen
Fast magnetosonic waves are one of the two low-frequency plasma modes that can exist in a neutron star magnetosphere. It was recently realized that these waves may become nonlinear…
Physics of Pair Producing Gaps in Black Hole Magnetospheres: Two Dimensional General Relativistic Particle-in-cell Simulations
Yajie Yuan, Alexander Y. Chen, Martin Luepker
Black holes can launch powerful jets through the Blandford-Znajek process. This relies on enough plasma in the jet funnel to conduct the necessary current. However, in some low lum…
Introducing APERTURE: A GPU-based General Relativistic Particle-in-Cell Simulation Framework
Alexander Y. Chen, Martin Luepker, Yajie Yuan
Low-luminosity Active Galactic Nuclei (AGN) are believed to be surrounded by a collisionless, highly magnetized accretion flow. As a result, Particle-in-Cell simulations are the be…
Alfvén Wave Conversion to Low Frequency Fast Magnetosonic Waves in Magnetar Magnetospheres
Dominic Bernardi, Yajie Yuan, Alexander Y. Chen
Rapid shear motion of magnetar crust can launch Alfvén waves into the magnetosphere. The dissipation of the Alfvén waves has been theorized to power the X-ray bursts characteristic…
Alfven Wave Mode Conversion in Neutron Star Magnetospheres: A Semi-analytic Approach
Alexander Y. Chen, Yajie Yuan, Dominic Bernardi
We write down the force-free electrodynamics (FFE) equations in dipole coordinates, and solve for normal modes corresponding to Alfvénic perturbations in the magnetosphere of a neu…
Physics of Pair Producing Gaps in Black Hole Magnetospheres II -- General Relativity
Alexander Y. Chen, Yajie Yuan
This is the second paper in a series where we examine the physics of pair producing gaps in low-luminosity accreting supermassive black hole systems. In this paper, we carry out ti…