Publications (77)
Two Phases of Particle Acceleration of a Solar Flare Associated with in situ Energetic Particles
Meiqi Wang, Bin Chen, Trevor Knuth +4
How impulsive solar energetic particle (SEP) events are produced by magnetic-reconnection-driven processes during solar flares remains an outstanding question. Here we report a sho…
Rapid variations of Si IV spectra in a flare observed by IRIS at a sub-second cadence
Juraj Lorincik, Vanessa Polito, Bart De Pontieu +2
We report on observations of highly-varying Si IV 1402.77 line profiles observed with the Interface Region Imaging Spectrograph (IRIS) during the M-class flare from 2022 January 18…
Fine Structures of Solar Radio Type III Bursts and their Possible Relationship with Coronal Density Turbulence
Xingyao Chen, Eduard P. Kontar, Sijie Yu +3
Solar radio type III bursts are believed to be the most sensitive signature of near-relativistic electron beam propagation in the corona. A solar radio type IIIb-III pair burst wit…
Microwave and Hard X-Ray Observations of the 2017 September 10 Solar Limb Flare
Dale E. Gary, Bin Chen, Brian R. Dennis +8
We report the first science results from the newly completed Expanded Owens Valley Solar Array (EOVSA), which obtained excellent microwave imaging spectroscopy observations of SOL2…
Machine Learning in Heliophysics and Space Weather Forecasting: A White Paper of Findings and Recommendations
Gelu Nita, Manolis Georgoulis, Irina Kitiashvili +38
The authors of this white paper met on 16-17 January 2020 at the New Jersey Institute of Technology, Newark, NJ, for a 2-day workshop that brought together a group of heliophysicis…
A model of double coronal hard X-ray sources in solar flares
Xiangliang Kong, Jing Ye, Bin Chen +6
A number of double coronal X-ray sources have been observed during solar flares by RHESSI, where the two sources reside at different sides of the inferred reconnection site. Howeve…
Microwave Spectral Imaging of an Erupting Magnetic Flux Rope: Implications for the Standard Solar Flare Model in Three Dimensions
Bin Chen, Sijie Yu, Katharine K. Reeves +1
We report microwave spectral imaging observations of an erupting magnetic flux rope during the early impulsive phase of the X8.2-class limb flare on 2017 September 10, obtained by…
All-Sky Ultra-Narrowband Spectral Imaging with the OVRO-LWA: Technosignature Constraints and Axion-Like Particle Prospects
Nikita Kosogorov, Gregg Hallinan, Greg Hellbourg +46
We present an imaging-domain search for technosignatures at decametric wavelengths with the OVRO-LWA, targeting ultra-narrowband continuous-wave signals between 50 and 86 MHz. We i…
Multi-Viewpoint Observation of a Failed Prominence Eruption on the Sun
Tingyu Gou, Katharine K. Reeves, Peter R. Young +5
Solar eruptions are sudden ejections of coronal mass and magnetic fields accompanied by intense energy release. The eruptive structure does not always erupt successfully, but somet…
Non-thermal Observations of a Flare Loop-top using IRIS Fe XXI: Implications for Turbulence and Electron Acceleration
William Ashfield, Vanessa Polito, Sijie Yu +2
The excess broadening of high-temperature spectral lines, long observed near the tops of flare arcades, is widely considered to result from magnetohydrodynamic (MHD) turbulence. Ac…
Implications for additional plasma heating driving the extreme-ultraviolet late phase of a solar flare with microwave imaging spectroscopy
Jiale Zhang, Bin Chen, Sijie Yu +6
Extreme-ultraviolet late phase (ELP) refers to the second extreme-ultraviolet (EUV) radiation enhancement observed in certain solar flares, which usually occurs tens of minutes to…
Radio Studies of the Middle Corona: Current State and New Prospects in the Next Decade
Bin Chen, Jason E. Kooi, David B. Wexler +13
The "middle corona," defined by West et al. (2022) as the region between ~1.5-6 solar radii, is a critical transition region that connects the highly structured lower corona to the…
The Origin of Underdense Plasma Downflows Associated with Magnetic Reconnection in Solar Flares
Chengcai Shen, Bin Chen, Katharine K. Reeves +3
Magnetic reconnection is a universal process that powers explosive energy release events such as solar flares, geomagnetic substorms, and some astrophysical jets. A characteristic…
Amplified J-factors in the Galactic Center for velocity-dependent darkmatter annihilation in FIRE simulations
Daniel McKeown, James S. Bullock, Francisco J. Mercado +6
We use FIRE-2 zoom cosmological simulations of Milky Way size galaxy halos to calculate astrophysical J-factors for dark matter annihilation and indirect detection studies. In addi…
Episodic energy release during the main- and post-impulsive phase of a solar flare
Yuqian Wei, Bin Chen, Sijie Yu +3
When and where the magnetic field energy is released and converted in eruptive solar flares remains an outstanding topic in solar physics. To shed light on this question, here we r…
Three-dimensional mapping of coronal magnetic field and plasma parameters in a solar flare
Tatyana Kaltman, Sijie Yu, Gregory D. Fleishman +1
Diagnosing solar flare conditions is essential for understanding coronal energy release. Using combined microwave and X-ray data, we reconstruct three-dimensional maps of the magne…
Estimating Electron Densities in the Middle Solar Corona using White-light and Radio Observations
Surajit Mondal, Shaheda Begum Shaik, Russell A. Howard +45
The electron density of the solar corona is a fundamental parameter in many areas of solar physics. Traditionally, routine estimates of coronal density have relied exclusively on w…
Starspots as the origin of ultrafast drifting radio bursts from an active M dwarf
Jiale Zhang, Hui Tian, Stefano Bellotti +16
Detecting coherent radio bursts from nearby M dwarfs provides opportunities for exploring their magnetic activity and interaction with orbiting exoplanets. However, it remains unce…
Energetic Electrons Accelerated and Trapped in a Magnetic Bottle above a Solar Flare Arcade
Bin Chen, Xiangliang Kong, Sijie Yu +6
Where and how flares efficiently accelerate charged particles remains an unresolved question. Recent studies revealed that a "magnetic bottle" structure, which forms near the botto…
The need for focused, hard X-ray investigations of the Sun
Lindsay Glesener, Albert Y. Shih, Amir Caspi +46
Understanding the nature of energetic particles in the solar atmosphere is one of the most important outstanding problems in heliophysics. Flare-accelerated particles compose a hug…
Microwave Imaging Spectroscopy Diagnosis of the Slow-rise Precursor of a Major Solar Eruption
Yuankun Kou, Xin Cheng, Sijie Yu +3
In this Letter, taking advantage of microwave data from the Expanded Owens Valley Solar Array and extreme-ultraviolet (EUV) data from the Atmospheric Imaging Assembly, we present t…
Doppler Signature of a Possible Termination Shock in an Off-Limb Solar Flare
Ryan J. French, Sijie Yu, Bin Chen +2
We report striking Doppler velocity gradients observed during the well-observed September 10th 2017 solar flare, and argue that they are consistent with the presence of an above-th…
Modeling the Thermal Low-Frequency Radio Sun with Ray Tracing
Peijin Zhang, Bin Chen, Gregory Fleishman +4
Incoherent radio emission at meter--decimeter wavelengths provides a key diagnostic of the coronal thermal plasma, but at frequencies below \,1\,GHz coronal refraction can su…
Fine structures of radio bursts from flare star AD Leo with FAST observations
Jiale Zhang, Hui Tian, Philippe Zarka +8
Radio bursts from nearby active M-dwarfs have been frequently reported and extensively studied in solar or planetary paradigms. Whereas, their sub-structures or fine structures rem…
Radio Spectral Imaging of an M8.4 Eruptive Solar Flare: Possible Evidence of a Termination Shock
Yingjie Luo, Bin Chen, Sijie Yu +2
Solar flare termination shocks have been suggested as one of the viable mechanisms for accelerating electrons and ions to high energies. Observational evidence of such shocks, howe…
Localising pulsations in the hard X-ray and microwave emission of an X-class flare
Hannah Collier, Laura A. Hayes, Sijie Yu +5
Aims: This work aims to identify the mechanism driving pulsations in hard X-ray (HXR) and microwave emission during solar flares. Here, by using combined HXR and microwave observat…
Energy budget in the 2017-09-07 "cold" solar flare
Gregory D. Fleishman, Galina G. Motorina, Sijie Yu +1
A subclass of early impulsive solar flares, cold flares, was proposed to represent a clean case, where the release of the free magnetic energy (almost) entirely goes to acceleratio…
Detection of long-lasting aurora-like radio emission above a sunspot
Sijie Yu, Bin Chen, Rohit Sharma +5
Auroral radio emissions in planetary magnetospheres typically feature highly polarized, intense radio bursts, usually attributed to electron cyclotron maser (ECM) emission from ene…
Numerical Modeling of Energetic Electron Acceleration, Transport, and Emission in Solar Flares: Connecting Loop-top and Footpoint Hard X-Ray Sources
Xiangliang Kong, Bin Chen, Fan Guo +8
The acceleration and transport of energetic electrons during solar flares is one of the outstanding topics in solar physics. Recent X-ray and radio imaging and spectroscopy observa…
Energy Evolution from the Chromosphere to the Heliosphere in the 2021 October 28 Solar Eruption
Katharine K. Reeves, Daniel B. Seaton, Cynthia Cattell +20
We perform a detailed study of the energetics for a well-observed solar eruption and flare that occurred on 28 October 2021. This event included a GOES class X1.0 flare, a global E…
Radio Imaging Spectropolarimetry of CMEs and CME Progenitors
Bin Chen, Timothy S. Bastian, Sarah Gibson +8
Coronal mass ejections (CMEs) are the most important drivers of space weather. Central to most CMEs is thought to be the eruption of a bundle of highly twisted magnetic field lines…
On the Nature of Candle-Flame-Shaped Solar Flares and Sub-Alfvénic Supra-Arcade Plasma Downflows
Ivan Oparin, Sabastian Fernandes, Bin Chen +4
Certain solar flares exhibit a distinctive candle-flame or cusp-shaped feature above the bright flare arcade visible in extreme ultraviolet (EUV) and X-ray channels sensitive to hi…
Radio Diagnostics of Particle Acceleration in Solar Flares with SKAO Observations
Rohit Sharma, Marina Battaglia, Sijie Yu +3
Particle acceleration is a fundamental astrophysical process occurring across diverse systems and scales, producing electromagnetic emission across all wavelengths. Radio bursts fr…
Radio and X-ray Observations of Short-lived Episodes of Electron Acceleration in a Solar Microflare
Rohit Sharma, Marina Battaglia, Yingjie Luo +2
Solar flares are sudden energy release events in the solar corona, resulting from magnetic reconnection, that accelerates particles and heats the ambient plasma. During a flare, th…
Evolution of Flare-accelerated Electrons Quantified by Spatially Resolved Analysis
Natsuha Kuroda, Gregory D. Fleishman, Dale E. Gary +3
Nonthermal electrons accelerated in solar flares produce electromagnetic emission in two distinct, highly complementary domains - hard X-rays (HXRs) and microwaves (MWs). This pape…
Coronal Magnetic Field Measurements along a Partially Erupting Filament in a Solar Flare
Yuqian Wei, Bin Chen, Sijie Yu +3
Magnetic flux ropes are the centerpiece of solar eruptions. Direct measurements for the magnetic field of flux ropes are crucial for understanding the triggering and energy release…
Effect of a sausage oscillation on radio zebra-pattern structures in a solar flare
Sijie Yu, V. M. Nakariakov, Yihua Yan
Sausage modes that are axisymmetric fast magnetoacoustic oscillations of solar coronal loops are characterized by variation of the plasma density and magnetic field, and hence caus…
Multiple Regions of Nonthermal Quasi-Periodic Pulsations during the Impulsive Phase of a Solar Flare
Yingjie Luo, Bin Chen, Sijie Yu +2
Flare-associated quasiperiodic pulsations (QPPs) in radio and X-ray wavelengths, particularly those related to nonthermal electrons, contain important information about the energy…
Measuring the Magnetic Field of a Coronal Mass Ejection from Low to Middle Corona
Xingyao Chen, Bin Chen, Sijie Yu +44
A major challenge in understanding the initiation and evolution of coronal mass ejections (CMEs) is measuring the magnetic field of the magnetic flux ropes (MFRs) that drive CMEs.…
Study of Particle Acceleration using Fine Structures and Oscillations in Microwaves from Electron Cyclotron Maser
Rohit Sharma, Marina Battaglia, Sijie Yu +3
The accelerated electrons during solar flares produce radio bursts and nonthermal X-ray signatures. The quasi-periodic pulsations (QPPs) and fine structures in spatial-spectral-tem…
Enigmatic centi-SFU and mSFU nonthermal radio transients detected in the middle corona
Surajit Mondal, Bin Chen, Sijie Yu +43
Decades of solar coronal observations have provided substantial evidence for accelerated particles in the corona. In most cases, the location of particle acceleration can be roughl…
Anisotropic Turbulent Flows Observed in Above the Loop-top Regions During Solar Flares
Xiaoyan Xie, Chengcai Shen, Katharine Reeves +6
Solar flare above-the-loop-top (ALT) regions are vital for understanding solar eruptions and fundamental processes in plasma physics. Recent advances in 3D MHD simulations have rev…
Radio Spectral Imaging and MHD Modeling of a CME-Driven Shock: Connecting Solar Type II Radio Bursts with Shock-Surface Magnetic Geometry
Peijin Zhang, Weihao Liu, Bin Chen +3
Solar type II radio bursts are widely regarded as signatures of shock waves propagating in the solar corona and are of particular importance for understanding shock-driven particle…
The bursty origin of the Milky Way thick disc
Sijie Yu, James S. Bullock, Courtney Klein +11
We investigate thin and thick stellar disc formation in Milky-Way-mass galaxies using twelve FIRE-2 cosmological zoom-in simulations. All simulated galaxies experience an early per…
Searches for Prompt Low-Frequency Radio Counterparts to Gravitational Wave Event S250206dm with the OVRO-LWA Time Machine
Nikita Kosogorov, Gregg Hallinan, Casey Law +46
We report on a search for prompt, low-frequency radio emission from the gravitational-wave (GW) merger S250206dm using the Owens Valley Radio Observatory Long Wavelength Array (OVR…
Born this way: thin disc, thick disc, and isotropic spheroid formation in FIRE-2 Milky-Way-mass galaxy simulations
Sijie Yu, James S. Bullock, Alexander B. Gurvich +7
We investigate the formation of Milky-Way-mass galaxies using FIRE-2 LCDM cosmological zoom-in simulations by studying the orbital evolution of stars formed in the main progenitor…
Hot Plasma Flows and Oscillations in the Loop-top Region During the September 10 2017 X8.2 Solar Flare
Katharine K. Reeves, Vanessa Polito, Bin Chen +4
In this study, we investigate motions in the hot plasma above the flare loops during the 2017 September 10 X8.2 flare event. We examine the region to the south of the main flare ar…
A Commensal Radio-Only Cosmic Ray Detector at the Owens Valley Radio Observatory Long Wavelength Array
Kathryn A. Plant, Andrew Romero-Wolf, Gregg Hallinan +46
The brief (10 nanoseconds) transient radio emission from cosmic ray air showers carries key information about the energy and mass composition of high energy cosmic rays, but anthro…
Radio Spectroscopic Imaging of a Solar Flare Termination Shock: Split-Band Feature as Evidence for Shock Compression
Bin Chen, Chengcai Shen, Katharine K. Reeves +2
Solar flare termination shocks have been suggested as one of the promising drivers for particle acceleration in solar flares, yet observational evidence remains rare. By utilizing…
A Joint Microwave and Hard X-Ray Study Towards Understanding the Transport of Accelerated Electrons during an Eruptive Solar Flare
Surajit Mondal, Andrea F. Battaglia, Bin Chen +1
The standard flare model, despite its success, is limited in comprehensively explaining the various processes involving nonthermal particles. One such missing ingredient is a detai…
Microwave Imaging of Quasi-periodic Pulsations at Flare Current Sheet
Yuankun Kou, Xin Cheng, Yulei Wang +4
Quasi-periodic pulsations (QPPs) are frequently detected in solar and stellar flares, but the underlying physical mechanisms are still to be ascertained. Here, we show microwave QP…
MeV-peaked electrons in a coronal source of a solar flare
Gregory D. Fleishman, Ivan Oparin, Gelu M. Nita +3
Analysis of γ-rays in solar flares has suggested a distinct continuum component dominating at MeV energies, which differs from the well-studied X-ray continuum produced by flare-a…
Possible First Detection of Gyroresonance Emission from a Coronal Mass Ejection in the Middle Corona
Surajit Mondal, Bin Chen, Xingyao Chen +45
Routine measurements of the magnetic field of coronal mass ejections (CMEs) have been a key challenge in solar physics. Making such measurements is important both from a space weat…
Spectral evolution of mildly relativistic electrons in solar flares
Gregory D. Fleishman, Tatyana Kaltman, Sijie Yu +1
Solar flares are a powerful engine capable of accelerating ambient plasma particles to high nonthermal energies. A key characteristic of these particles is their energy spectrum. N…
Probing the Turbulent Corona and Heliosphere Using Radio Spectral Imaging Observation during the Solar Conjunction of Crab Nebula
Peijin Zhang, Surajit Mondal, Bin Chen +41
Measuring plasma parameters in the upper solar corona and inner heliosphere is challenging because of the region's weakly emissive nature and inaccessibility for most in situ obser…
MC-GPT: Empowering Vision-and-Language Navigation with Memory Map and Reasoning Chains
Zhaohuan Zhan, Lisha Yu, Sijie Yu +1
In the Vision-and-Language Navigation (VLN) task, the agent is required to navigate to a destination following a natural language instruction. While learning-based approaches have…
Magnetic Reconnection Null Points as the Origin of Semi-relativistic Electron Beams in a Solar Jet
Bin Chen, Sijie Yu, Marina Battaglia +7
Magnetic reconnection, the central engine that powers explosive phenomena throughout the Universe, is also perceived as one of the principal mechanisms for accelerating particles t…
The Solar Origin of an In Situ Type III Radio Burst Event
Meiqi Wang, Bin Chen, Sijie Yu +4
Solar type III radio bursts are generated by beams of energetic electrons that travel along open magnetic field lines through the corona and into interplanetary space. However, und…
Summary of the First Year of the Space Weather Around Young Suns Program: 900 Hours of Low-frequency Radio and Optical Data Dedicated to Young, Solar-type Stars
Ivey Davis, Gregg Hallinan, Nikita Kosogorov +51
The Space Weather Around Young Suns (SWAYS) program was introduced in \citet{Davis2025} as a multi-wavelength monitoring program for studying the activity and particle environments…
Galaxies lacking dark matter produced by close encounters in a cosmological simulation
Jorge Moreno, Shany Danieli, James S. Bullock +18
The standard cold dark matter plus cosmological constant model predicts that galaxies form within dark-matter haloes, and that low-mass galaxies are more dark-matter dominated than…
Implementation of a Near-Realtime Recording and Reporting System of Solar Radio Bursts
Peijin Zhang, Anastasia Kuske, Bin Chen +48
Strong solar activity is often accompanied by a variety of radio bursts. These bursts are valuable diagnostics of coronal and heliospheric processes and also have potential applica…
Measurement of magnetic field and relativistic electrons along a solar flare current sheet
Bin Chen, Chengcai Shen, Dale E. Gary +8
In the standard model of solar flares, a large-scale reconnection current sheet is postulated as the central engine for powering the flare energy release and accelerating particles…
Solar LImb Prominence CAtcher and Tracker (SLIPCAT): An Automated System and Its Preliminary Statistical Results
Yuming Wang, Hao Cao, Junhong Chen +6
In this paper, we present an automated system, which has the capability to catch and track solar limb prominences based on observations from EUV 304 passband. The characteristic pa…
Spectral Observations and Modeling of a Solar White-light Flare Observed by CHASE
De-Chao Song, Jun Tian, Y. Li +11
The heating mechanisms of solar white-light flares remain unclear. We present an X1.0 white-light flare on 2022 October 2 (SOL2022-10-02T20:25) observed by the Chinese \ha\ Solar E…
Hot-mode accretion and the physics of thin-disk galaxy formation
Zachary Hafen, Jonathan Stern, James Bullock +16
We use FIRE simulations to study disk formation in z~0, Milky Way-mass galaxies, and conclude that a key ingredient for the formation of thin stellar disks is the ability for accre…
Stars made in outflows may populate the stellar halo of the Milky Way
Sijie Yu, James S. Bullock, Andrew Wetzel +8
We study stellar-halo formation using six Milky Way-mass galaxies in FIRE-2 cosmological zoom simulations. We find that of the outer ( kpc) stellar halo in each sy…
Few Made It Out: A Multi-Messenger Study of an In Situ Solar Energetic Electron Event Driven by a Solar Jet
Meiqi Wang, Bin Chen, Mallory Wickline +4
When in situ solar energetic electron (SEE) events are closely associated with nonthermal flares, the escaping electron population is frequently observed to be much smaller than th…
Quantifying Energy Release in Solar Flares and Solar Eruptive Events: New Frontiers with a Next-Generation Solar Radio Facility
Bin Chen, Dale E. Gary, Sijie Yu +16
Solar flares and the often associated solar eruptive events serve as an outstanding laboratory to study the magnetic reconnection and the associated energy release and conversion p…
Non-thermal Broadening of IRIS Fe XXI Lines Caused by Turbulent Plasma Flows in the Magnetic Reconnection Region During Solar Eruptions
Chengcai Shen, Vanessa Polito, Katharine K. Reeves +3
Magnetic reconnection is the key mechanism for energy release in solar eruptions, where the high-temperature emission is the primary diagnostic for investigating the plasma propert…
Multifrequency microwave imaging of weak transients from the quiet solar corona
Surajit Mondal, Bin Chen, Sijie Yu
Understanding the dynamics of the quiet solar corona is important for answering key questions including the coronal heating problem. Multiple studies have suggested small-scale mag…
Energy Conversion and Electron Acceleration and Transport in 3D Simulations of Solar Flares
Xiaocan Li, Chengcai Shen, Xiaoyan Xie +6
Recent observations and simulations indicate that solar flares undergo extremely complex three-dimensional (3D) evolution, making 3D particle transport models essential for underst…
Possible Detection of Subsecond-period Propagating Magnetohydrodynamics Waves in Post-reconnection Magnetic Loops during a Two-ribbon Solar Flare
Sijie Yu, Bin Chen
Solar flares involve the sudden release of magnetic energy in the solar corona. Accelerated nonthermal electrons have often been invoked as the primary means for transporting the b…
Dynamics of the coronal magnetic field in the 2022-10-02 X-class flare
Gregory D. Fleishman, Tatyana Kaltman, Sijie Yu
Solar flares are driven by release of free magnetic energy and often associated with restructurization of the magnetic field topology. Yet, observations of evolving magnetic field…
Multiple electron acceleration instances during a series of solar microflares observed simultaneously at X-rays and microwaves
Marina Battaglia, Rohit Sharma, Yingjie Luo +3
Even small solar flares can display a surprising level of complexity regarding their morphology and temporal evolution. Many of their properties, such as energy release and electro…
Quasi-periodic wiggles of microwave zebra structures in a solar flare
Sijie Yu, V. M. Nakariakov, L. A. Selzer +2
Quasi-periodic wiggles of microwave zebra pattern structures with period range from about 0.5 s to 1.5 s are found in a X-class solar flare on 2006 December 13 at the 2.6-3.8 GHz w…
Magnetic Reconnection During the Post-Impulsive Phase of a Long-Duration Solar Flare: Bi-Directional Outflows as a Cause of Microwave and X-ray Bursts
Sijie Yu, Bin Chen, Katharine K. Reeves +5
Magnetic reconnection plays a crucial role in powering solar flares, production of energetic particles, and plasma heating. However, where the magnetic reconnections occur, how and…
Relaxation of magnetic field relative to plasma density revealed from microwave zebra patterns associated with solar flares
Sijie Yu, Yihua Yan, Baolin Tan
It is generally considered that the emission of microwave zebra pattern (ZP) structures requires high density and high temperatures, which is similar to the situation of the flarin…