2026 Simons Collaboration on Extreme Electrodynamics of Compact Sources Annual Meeting

The Simons Collaboration on Extreme Electrodynamics of Compact Sources, SCEECS, held its third annual meeting at the Simons Foundation in New York on February 26–27, 2026.

There were 121 in person participants from around the world, including all ten PIs, seven out of nine Co-Is, and six out of eleven members of the Advisory Board. Researchers from the astrophysics, condensed matter, cosmology, light source, nuclear physics, particle physics, plasma, relativity and space physics communities were also heavily engaged. Progress with and the promise of powerful codes developed by SCEECS members — which are now functioning like new observatories — featured prominently in the meeting. More detail can be found on the collaboration website: https://www.simonsceecs.com.

The meeting began with a program overview by Director Blandford, who introduced the two new PIs, Beloborodov and Quataert, the rotated Advisory Board, and many new SCEECS members. Blandford explained the transition of the scientific organization from neutron stars and black holes to four physical processes, described in the ensuing six talks by the original PIs on neutron stars, magnetars, FRB, particle acceleration, black holes, and magnetized flows.

Radiative Processes: Considerable progress on the greatest challenge — explaining coherent radio emission from FRB and pulsars — was reported. FRB, which occur roughly once a minute, may have several origins, but most are associated with magnetars — neutron stars with surface fields as large as 1015G, ~20 times the Schwinger field. FRB are proving to be powerful probes of the disposition of baryons in the universe. They may form close to the neutron star, as strongly relativistic electromagnetic pulses, but they are then subject to absorption and scattering through parametric instability. Alternatively, they may originate from maser-like processes within “monster” shocks at greater distance. Simulations are elucidating the physics of these competing explanations, as well as others that may be relevant to the larger class of FRB. Pulsar x-ray emission originates from near the light cylinder, and there are now convincing explanations of some of the radio emission associated with current sheets there. Most pulsar radio emission originates closer to the star and promising new mechanisms are under investigation.

Magnetized Flow: Millimeter VLBI observations, infrared interferometry, and X-ray polarimetry are showing us that spinning, magnetized neutron stars and black holes can drive giant electrical circuits. In the case of black holes, more attention is being paid to the underlying question of how much of the mass supplied at large radius accretes onto the black hole, how much is driven away in a wind, and how do the energy and magnetic field flow on average. Large scale MHD simulations have encompassed scales from the Bondi radius to the horizon and have interfaced with subgrid microphysics. Particular attention is being paid to the structure of and emission from coronae and the powerful relativistic jets associated with AGN and GRB and their observed dissipation. Jet magnetic structure, revealed by polarization, can be matched to the underlying disks. Similar questions are being answered with models of tidal disruption events. A very new, and possibly important, example of this gas flow is provided by the “little red dots,” which are widely believed to be nascent black holes in the early stages of quasar and galaxy formation.

Extreme Magnetic Field: Modeling of neutron star cores and, especially, crusts has improved dramatically using molecular dynamics simulations to measure elastic and transport properties and uncover crucial, non-ideal physics. These calculations allow exploration of the slow evolution of the magnetic field through Hall waves and provide the all-important connection to the magnetosphere, made manifest through glitches, timing noise and flares. Magnetars can undergo giant X-ray flares, as well as FRB, through the release of magnetic energy. Modeling of the flare dynamics has greatly improved, distinguishing twisting from shaking motions of the field and is confronting existing and anticipated observations. Under some circumstances, these processes might be used to detect the presence of axions.

Particle Acceleration: Particle acceleration pervades most SCEECS investigations from the mildly nonthermal plasmas in coronae to the extreme accelerators needed to account for PeV x-rays, Pev xs, and near ZeV cosmic rays. There has been considerable progress on the three principal mechanisms, based upon turbulence, especially associated with dynamos, magnetic reconnection, and collisionless shock fronts. This has been largely developed through increasingly detailed, 3D numerical simulations, especially PIC codes, including radiative processes, and applied to disks, coronae, jet sheaths, neutron star mergers, magnetospheric flares, and current sheets, which exhibit great diversity in the underlying physical conditions. Each of these mechanisms is nonlinear in the sense that back-reaction of the accelerated particle influences the dynamics and the injection of low energy particles.

The meeting concluded with an outline of the proposed, future program out to August 2030 by the Deputy Director Philippov, emphasizing theoretical investigations selected to complement a transformative wave of new observation by radio telescopes and multi-wavelength and messenger searches that will probe the rich phenomenology of FRB. In addition, he outlined a program to calculate the properties of thick and thin, strongly magnetized disks orbiting black holes. The resurgence of interest in the physics of neutron star crusts and cores will continue and their magnetic behavior will be explored, so as to sharpen our understanding of the equation of state of cold, nuclear matter. Models of neutron star magnetospheres, as inferred by NICER, will be refined in time for its Chinese successor eXTP. Particle acceleration investigations are likely to expand from local to global consideration. He also described new codes, developed under SCEECS, including Entity — an architecture agnostic PIC code — and Gkeyll, a relativistic Vlasov code which are making predictive models of the most extreme environments in the universe.

The collaboration meeting was followed by a 1.5-day satellite meeting which featured two debates (on whether M87 is powered by accreting gas or black hole spin and whether FRB emission from magnetars arises near or far from the star), six panels (on modeling jets, emission from close to black holes, neutron star magnetospheres, neutron star interiors, magnetic reconnection, and PeVatrons), and seven talks by junior members. There were 22 excellent posters displayed at both meetings, and the education/outreach program was described and discussed.

SCEECS thanks the Simons Foundation for its ongoing support, gracious hospitality, and efficient organization. This facilitates effective communication of progress, fosters collegial discussion of promising approaches to answering the exciting scientific questions that fascinate us all, and provides a foundation for addressing the unscripted discovery that is sure to come.

Roger Blandford
Stanford University

Simons Collaboration on Extreme Electrodynamics of Compact Sources – Progress
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In its first two and a half years, the SCEECS collaboration has addressed the exciting discoveries being made from observations of black holes and neutron stars, involving magnetic fields of ~ 10^15 G, voltages up to 10^23 V, powers up to 10^49 W and effective temperature of more than 10^40 K which has taken classical electromagnetism and quantum electrodynamics into new territory. We have developed new theoretical approaches that address questions of fundamental physics and make phenomenological contact with models of specific sources, often involving state-of-the-art simulations. These methods are also relevant to upcoming laboratory experiments.
 

Yuri Levin
Columbia University

Exotic Dynamics of Neutron Star Interiors

Quantum fluids, crystal lattice, magnetic fields, and conducting electrons are strongly coupled inside a neutron star. Their coupling to the exterior, the neutron star magnetosphere, leads to observable consequences. This talk will highlight giant Hall waves triggered by superconducting transition in the neutron star core, dynamics of the superfluid vortices and of the crystal lattice in the inner crust, Landau quantization of the electron states, and magnetically driven baryonic eruptions.
 

Amir Levinson
Tel Aviv University

Physics of Fast Radio Bursts
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Fast radio bursts (FRBs) are extremely short, intense flashes of radio waves originating at extragalactic distances. They exhibit a wide range of unusual properties, offering a unique opportunity to probe plasma physics in regimes that have not been previously explored. There is compelling evidence that at least some FRBs originate from magnetars, likely triggered by the sudden release of magnetic stresses. In this talk, recent progress and future challenges in modeling the generation and propagation of FRBs and connecting to upcoming stunning observations will be summarized.
 

Sasha Philippov
University of Maryland

Simons Collaboration on Extreme Electrodynamics of Compact Sources – Future Program
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The second half of the decade promises spectacular advances in the extreme astrophysics of compact objects, among which are precise localizations of multiple fast radio bursts and detection of their potential high-energy counterparts, major progress in constraining the equation of state of dense nuclear matter, and detections of ultra-high-energy nuclei, photons, and neutrinos. Multiple competing paradigms have been proposed to explain these phenomena. The goal of the SCEECS collaboration is to explore the underlying fundamental physical processes, especially using powerful simulations, enabling decisive discrimination among competing models through observations. This talk will outline our future research program, structured around four principal physics themes: (1) emission mechanisms, (2) extreme magnetic fields, (3) magnetized plasma flows, and (4) particle acceleration, as well as our new organization and our educational program.
 

Tsvi Piran
Hebrew University of Jerusalem

Understanding Black Holes
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Although nothing can escape from cosmic black holes, the power the universe’s most luminous phenomena through accretion and rotational energy, mediated by electromagnetic and general relativistic effects. Multi-messenger observations involving photons, gravitational-waves, neutrinos, and cosmic rays have recently enabled us to probe their properties, especially close to the event horizon. I will present the advances in modeling these processes from the SCEECS collaboration toward understanding the behavior of black holes.
 

Chris Thompson
University of Toronto

Magnetars
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Magnetars are young neutron stars with extreme, super-Schwinger, magnetic fields, ~10^(15)G. They are sources of soft gamma-ray and fast radio bursts. Electric currents circulating in their magnetospheres drive a bright flux of X-rays that carries the imprint of QED interactions. Much has been learned about plasma physics in these exotic environments, as well as using them as tests of physics beyond the standard model, e.g., light axions. This talk will highlight recent advances in modeling energy release and observable implications for pulsed and bursting X-ray and radio sources.
 

Anatoly Spitkovsky
Princeton University

Particle Acceleration in Extreme Environments

Energetic particles, with energies up to 3 x 10^20 eV, are observed through electromagnetic and multimessenger observations of compact sources. The ubiquity of power law spectra in observed sources suggests that particle acceleration is often a self-correcting process where the feedback of accelerated particles on the environment is important for the mechanism to work. This talk will review the status and plans for understanding particle acceleration in different conditions, emphasizing recent progress on simulating multiscale feedback in shocks, reconnection, and turbulence.
 

Ellen Zweibel
University of Wisconsin — Madison

Magnetized Flow around Black Holes
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The gas that flows onto black holes through accretion disks and coronas and away from them as relativistic jets and winds is inevitably magnetized. This magnetic field is central to the large-scale dynamics of the flow and the microphysical processes responsible for what is observed. The regeneration of magnetic field through novel dynamo processes involving magnetic helicity transport and its decay through particle acceleration and dissipation will be described. A rich variety of mechanisms is needed to accommodate the diversity of the sources.

Watch a playlist of all presentations from this meeting here.