170 citations · 711 across the 21 of their papers we have counts for
21 papers
Evaluation of several explanations of the strong X-ray polarization of the black hole X-ray binary 4U 1630-47
Henric Krawczynski, Yajie Yuan, Alexander Y. Chen +6
The Imaging X-ray Polarimetry Explorer (IXPE) observations of the X-ray binary 4U 1630-47 in the high soft state revealed high linear polarization degrees (PDs) rising from 6% at 2…
Propagation of a Strong Fast Magnetosonic Wave in the Magnetosphere of a Neutron Star
Alexander Y. Chen, Yajie Yuan, Xinyu Li +1
We study the propagation of a strong, low frequency, linearly polarized fast magnetosonic wave inside the magnetosphere of a neutron star. The relative strength of the wave…
Synchrotron Pair Production Equilibrium in Relativistic Magnetic Reconnection
Alexander Y. Chen, Dmitri Uzdensky, Jason Dexter
Magnetic reconnection is ubiquitous in astrophysical systems, and in many such systems, the plasma suffers from significant cooling due to synchrotron radiation. We study relativis…
Novel Constraints on Axions Produced in Pulsar Polar-Cap Cascades
Dion Noordhuis, Anirudh Prabhu, Samuel J. Witte +3
Axions can be copiously produced in localized regions of neutron star magnetospheres where the ambient plasma is unable to efficiently screen the induced electric field. As these a…
Magnetar bursts due to Alfvén wave nonlinear breakout
Yajie Yuan, Andrei M. Beloborodov, Alexander Y. Chen +3
The most common form of magnetar activity is short X-ray bursts, with durations from milliseconds to seconds, and luminosities ranging from to $10^{43}\ {\rm erg}\,{\rm s…
Kinetic Simulations of Instabilities and Particle Acceleration in Cylindrical Magnetized Relativistic Jets
José Ortuño-Macías, Krzysztof Nalewajko, Dmitri A. Uzdensky +4
Relativistic magnetized jets, such as those from AGN, GRBs and XRBs, are susceptible to current- and pressure-driven MHD instabilities that can lead to particle acceleration and no…
Relativistic wind from a magnetic monopole rotator
Rui Hu, Andrei M. Beloborodov, Alexander Y. Chen
A rotating star with a monopole (or split monopole) magnetic field gives the simplest, prototype model of a rotationally driven stellar wind. Winds from compact objects, in particu…
Radiation GRMHD simulations of M87: funnel properties and prospects for gap acceleration
Philippe Z. Yao, Jason Dexter, Alexander Y. Chen +2
We use the public code ebhlight to carry out 3D radiative general relativistic magnetohydrodynamics (GRMHD) simulations of accretion onto the supermassive black hole in M87. The si…
Coherent emission from QED cascades in pulsar polar caps
Fábio Cruz, Thomas Grismayer, Alexander Y. Chen +2
Pulsar magnetospheres are thought to be filled with electron-positron plasma generated in pair cascades. The driving mechanism of these cascades is the emission of gamma-ray photon…
Relativistic Alfvén Waves Entering Charge Starvation in the Magnetospheres of Neutron Stars
Alexander Y. Chen, Yajie Yuan, Andrei M. Beloborodov +1
Instabilities in a neutron star can generate Alfvén waves in its magnetosphere. Propagation along the curved magnetic field lines strongly shears the wave, boosting its electric cu…
Plasmoid ejection by Alfvén waves and the fast radio bursts from SGR 1935+2154
Yajie Yuan, Andrei M. Beloborodov, Alexander Y. Chen +1
Using numerical simulations we show that low-amplitude Alfvén waves from a magnetar quake propagate to the outer magnetosphere and convert to "plasmoids" (closed magnetic loops) wh…
A Numerical Model for the Multi-wavelength Lightcurves of PSR J0030+0451
Alexander Y. Chen, Yajie Yuan, Georgios Vasilopoulos
Recent modeling of Neutron Star Interior Composition Explorer(NICER) observations of the millisecond pulsar PSR J0030+0451 suggests that the magnetic field of the pulsar is non-dip…
Filling the Magnetospheres of Weak Pulsars
Alexander Y. Chen, Fabio Cruz, Anatoly Spitkovsky
Recent advances in numerical algorithms and computational power have enabled first-principles simulations of pulsar magnetospheres using Particle-in-Cell (PIC) techniques. These ab…
Inverse Compton Cascades in Pair-Producing Gaps: Effects of Triplet Pair Production
Maria Petropoulou, Yajie Yuan, Alexander Y. Chen +1
Inverse Compton-pair cascades are initiated when gamma-rays are absorbed on an ambient soft photon field to produce relativistic pairs, which in turn up-scatter the same soft photo…
Detecting Axion Dark Matter with Radio Lines from Neutron Star Populations
Benjamin R. Safdi, Zhiquan Sun, Alexander Y. Chen
It has been suggested that radio telescopes may be sensitive to axion dark matter that resonantly converts to radio photons in the magnetospheres surrounding neutron stars (NSs). I…
Numerical methods for General Relativistic particles
Fabio Bacchini, Bart Ripperda, Lorenzo Sironi
We present recent developments on numerical algorithms for computing photon and particle trajectories in the surrounding of compact objects. Strong gravity around neutron stars or…
Physics of Pair Producing Gaps in Black Hole Magnetospheres
Alexander Y. Chen, Yajie Yuan, Huan Yang
In some low-luminosity accreting supermassive black hole systems, the supply of plasma in the funnel region can be a problem. It is believed that a local region with unscreened ele…
Generalized, energy-conserving numerical simulations of particles in general relativity. I. Time-like and null geodesics
Fabio Bacchini, Bart Ripperda, Alexander Yuran Chen +1
The numerical integration of particle trajectories in curved spacetimes is fundamental for obtaining realistic models of the particle dynamics around massive compact objects such a…
Particle-in-cell simulations of the twisted magnetospheres of magnetars
Alexander Y. Chen, Andrei M. Beloborodov
The magnetospheres of magnetars are believed to be filled with electron-positron plasma generated by electric discharge. We present a first direct numerical experiment showing how…
Electrodynamics of axisymmetric pulsar magnetosphere with electron-positron discharge: a numerical experiment
Alexander Y. Chen, Andrei M. Beloborodov
We present the first self-consistent global simulations of pulsar magnetospheres with operating discharge. We focus on the simple configuration of an aligned or anti-aligne…
Dead zone in the polar-cap accelerator of pulsars
Alexander Y. Chen, Andrei M. Beloborodov
We study plasma flows above pulsar polar caps using time-dependent simulations of plasma particles in the self-consistent electric field. The flow behavior is controlled by the dim…