Advanced Accelerator Concepts 2026

Working Groups

WG1 : Laser plasma acceleration of leptons

AAC 2026 Working Group 1 coLeaders: Alex Picksley (LBNL), Ela Rockafellow(Maryland), Min Sup Hur (UNIST)

Working Group 1 will discuss progress and advanced concepts in laser-driven wakefield acceleration (LWFA). LWFA technology has potential applications for example to future TeV-scale colliders, as well as compact secondary radiation sources (e.g. plasma-based X-FELs or high-field THz) . Participants are encouraged to present research results that show a path towards improving the performance of LWFA for these and other applications. This working group welcomes presentation of experimental, simulation, and theoretical results. The following topics are of particular interest:

• High beam quality (including energy spread, current and emittance). How to achieve robust, high-quality injection into the wake? How to preserve beam quality throughout an accelerator with one or several plasma acceleration stages? How can advances in compact beam manipulation and transportation techniques further improve beam quality?

• High beam energy. How to mitigate limitations on beam energy, such as dephasing, depletion and laser diffraction? How can laser pulse shaping and plasma tailoring (e.g. plasma waveguides) be leveraged to overcome some of these limitations? How to maximize laser-to-beam energy transfer? 

• Stable, high-repetition-rate operation. How can new laser-plasma concepts, as well as progress in plasma, laser technology, and advanced algorithms (including data-driven ML/AI) enhance shot-to-shot stability and enable higher repetition rates? 

• Wakefield acceleration of positrons and other exotic particles. Are there schemes and techniques that potentially allow to obtain the above properties (high beam quality, energy, stability, or high repetition rate) for positron beams? Are there new ideas on how to overcome the experimental challenges of positron trapping/acceleration in laser-driven wakefield?

• Diagnostics and Applications. How can one measure key beam quality parameters such as (slice) emittance, (slice) energy spread, (slice) current? Which applications may be enabled by certain combinations of characteristics, such as high 6D brightness for light sources, or high current for using electron beams from LWFA as drivers for PWFA?

• Computational techniques. Are there new algorithms and simulation techniques (including AI/ML-aided techniques) that can help answer the above questions more efficiently and/more with more accuracy?

WG2 : Laser-driven plasma acceleration of ions 

AAC2026 Working Group 2 coLeaders: Nicholas Dover (Imperial), Aodhan McIlvenny (LBNL) 

Advanced ion beam sources, driven by high intensity laser interactions with matter, offer a compact and versatile alternative to radiofrequency accelerators. Additionally, these MeV energy sources can provide high particle flux in an ultra-short duration leading to uniquely high dose rates. The commissioning of suitable targetry with both sub-PW and multi-PW lasers, have demonstrated advanced ion acceleration mechanisms as well as the optimization of thermally driven acceleration. These have been informed and motivated by the use and development of higher fidelity simulations exploring the underlying physics. Furthermore, high repetition rate experiments have enabled the use of AI/ML to inform and optimize experiments together with digital twins. This diverse research field explores the variety of acceleration mechanisms, post-acceleration beam capturing and transport and applications ranging from cancer therapy to fast-ignition fusion.

We  invite contributions to Working Group 2 that present new results and initiatives of experimental, theoretical and computational studies in laser-driven ion acceleration, including proton and heavier-ion generation

• progress towards higher ion beam energy and luminosity
  
  

• beam transport and manipulation
  
  

• novel instrumentation,  including targetry and particle diagnostics
  
  

• generation of secondary radiation and particle sources
  
  

• present and future applications
  
  

• Original, status and review papers are welcome.

WG3 : Beam-Driven Plasma Wakefield Acceleration 

AAC2026 Working Group 3 coLeaders: Doug Storey (SLAC), Livio Verra (INFN-LNF)

In WG3, we will discuss the current status, recent breakthroughs, and longstanding challenges in beam-driven plasma wakefield acceleration (PWFA), which offers ultra-high accelerating gradients suitable for compact colliders, light sources, and related applications. We welcome presentations on topics such as (including those of interest to multiple working groups):

• Beam-plasma dynamics and interactions, efficient wake excitation, energy depletion and witness acceleration, high transformer-ratio, emittance and energy spread preservation.
  
  

• Beam-plasma instabilities, beam stability in plasma, phase space shaping and control, ion motion.
  
  

• Plasma sources, plasma density profile shaping and control, plasma density characterization
  
  

• Advances in PWFA simulations and in new acceleration schemes
  
  

• Beam-plasma radiation generation for sources and diagnostics
  
  

• Schemes for HEP PWFA linacs (10 TeV, Alive, HALHF, etc..), staging, positron acceleration
  
  

• Discussion of results that are not yet fully characterized or otherwise peculiar in nature, as well as progress and challenges faced during experiments
  
  

• Outlook on the field and roadmap for the future
  
  

WG4: Advanced Structure Acceleration (Beam, RF, or Laser Driven)

AAC2026 Working Group 4 coLeaders: Gongxiaohui Chen (ANL), Tianhuan Luo(LBNL) 

Working Group 4 addresses key challenges in developing advanced structure-based accelerators driven by external electromagnetic sources (RF, THz, laser) or by beam-driven wakefields. The capability to achieve higher accelerating gradients, improved efficiency, and robust operation is essential for reducing the size and cost of future accelerators for High Energy Physics, as well as for applications in Basic Energy Sciences, Nuclear Physics, National Security, industry, and medicine. This includes future multi-TeV lepton collider concepts, compact high-brightness linacs, next-generation FEL injectors, and high-gradient structures for compact or portable accelerator systems.

WG4 welcomes contributions on:

• Novel accelerating structures, including new geometries, materials (metallic, dielectric, metamaterial, hybrid), and new fabrication techniques (additive manufacturing, micromachining), spanning microwave to THz and optical frequencies;

• Physics limits to gradient, such as RF breakdown, surface heating, and temperature-dependent and short-pulse effects;

• Efficiency enhancements, including low-loss materials, distributed power-coupling schemes, and high-efficiency beam-loading concepts;

• Experimental demonstrations of high-gradient operation in RF-, THz-, laser-, and beam-driven structures;

• Special operating regimes, including NCRF cavities in magnetic fields and alternative concepts such as high-pressure gas-filled structures;

• High-brightness photoinjectors and ultrafast electron sources;

• Modeling and simulation challenges, including structure–beam interactions, structure heating, and predictive breakdown models;

• Electromagnetic power sources and delivery systems optimized for advanced accelerating structures.

WG5 : Beam Generation, Dynamics, Diagnostics and Control

AAC 2026 Working Group 5 coLeaders: Jared Maxson (Cornell) and Ryan Roussel (SLAC)

Working Group 5 will address the three subjects in its title:

• Beam generation:  Advanced accelerators and beam sources require and/or generate beams with unique characteristics, including short bunch lengths, high peak currents, high bunch charges, small uncorrelated energy spreads, low transverse emittance, complex beam shapes, high purity for proton/ion sources, and small pointing and timing jitters, all relative to the state of the art.  The working group will seek to both survey these state of the art and explore technologies that may surpass them.
• Diagnostics and Control: Advanced accelerator concepts demand precise, real-time characterization and control of both beam and accelerator dynamics to achieve optimal performance and reliability. This encompasses diagnostics and control of the accelerated beam, the accelerating medium, and the wakefield driver (e.g., plasma, structure, or RF systems). This working group focuses on the development and integration of advanced diagnostic techniques, control strategies, novel beam manipulations including phase space cooling and enabling technologies to meet these challenges. Emphasis is placed on innovative approaches—including artificial intelligence and machine learning—to enable robust operation, enhanced performance, and scalability of advanced accelerator systems.
• Beam Dynamics: Advanced accelerators present significant challenges and opportunities in novel beam dynamics, driven by either external fields or collective effects. Beam dynamics is often strongly coupled with generation, control, and diagnostics as described above. As such,  this working group includes discussion of novel beam dynamics phenomena not addressed in other working groups, particularly with emphasis on the intersection of dynamics with other topics covered by this working group.

We invite presentations, both theoretical and experimental, in the above areas as well as other related subjects. Results of this assessment will be written and distributed as a working group summary. Joint sessions with other working groups on the topics of beam generation, diagnostics and control/manipulation will be considered.

 

WG6 : Radiation generation, medical and industrial applications

AAC 2026 Working Group 6 coLeaders: Sarah Schröder (LBNL) and Agostino Marinelli (SLAC)

An abundance of applications of advanced particle accelerators and their associated radiation sources (electrons, protons, muons, X-rays, gammas, etc.) have emerged in recent years, driving innovation and discovery across industrial, medical, and fundamental science. Working Group 6 will address recent progress and highlight results related to these applications and their broad societal and scientific impact beyond the advanced accelerator community.

We encourage participants to contribute experimental and theoretical work on the applications of beam- and laser-driven radiation (particle or photon) sources. Specific areas of focus include free-electron lasers, Compton/Thomson scattering, bremsstrahlung, betatron radiation, THz generation, alongside muon beam generation and direct applications of AAC particle sources in industrial and medical sectors. 

We invite authors to contribute talks which emphasize the unique properties of AAC-driven radiation sources, such as advanced control of the spatio-temporal radiation properties, source polarization, ultra-short pulse generation, source flexibility and tunability. We also invite contributions considering opportunities enabled by novel compact source designs and improvements in source stability and reproducibility to serve different applications. We encourage highlighting the user demands and necessary developments for timely application transfer.

WG7: Colliders and near term HEP applications

AAC 2026 working group 7 coleaders: Philippe Piot (ANL), Diktys Stratakis (FNAL) and Tor Raubenheimer (SLAC)

Working Group 7 will discuss recent progress and chart the future path toward energy-frontier lepton colliders based on wakefield acceleration (WFA) technologies, as well as integrated designs for energy-frontier muon colliders.  The discussion will focus on advancing collider concepts that push the boundaries of the energy frontier while also providing pathways to Higgs factories. Additionally, we aim to explore potential near-term applications of these proposed concepts as integrated facilities that serve end users from high-energy physics, nuclear physics, or basic energy sciences. We will assess the current state of the art and analyze key challenges facing these transformative technologies. 

Specifically, Working Group 7 will: 

• Discuss recent advancements in theoretical, numerical, and experimental work encompassing all aspects of collider physics, including source/injector systems, beam polarization, linac design, energy efficiency, stability, beam quality preservation, staging strategies, tolerances, beam-delivery systems, and final focus;
  
  

• Explore integrated designs for muon colliders, focusing on their potential to achieve energy-frontier performance and their role in enabling Higgs factory applications. This includes addressing challenges such as the production of intense muon beams, rapid beam cooling before muon decay, mitigation of severe detector backgrounds from muon decays, and the design of high-field magnets and RF systems.
  
  

• Present conceptual designs for muon colliders, WFA-based linear colliders, and other HEP applications for high energy lepton beams.  Discuss plans for future integrated design studies, as recommended in the 2023 P5 [https://doi.org/10.2172/2368847 ] and 2025 National Academies of Sciences, Engineering, and Medicine [https://doi.org/10.17226/28839] reports.
  
  

• Analyze potential near-term applications of these technologies as integrated facilities that can serve end users from high-energy physics, nuclear physics, or basic energy sciences, fostering interdisciplinary collaboration and maximizing the impact of these advancements.
  
  

• Examine necessary infrastructure for near-term test facilities (for component testing) and demonstrator facilities (for integration testing) on the pathway to realizing these colliders.

Participants are encouraged to highlight their recent contributions to these topics in their presentations and, in the spirit of this workshop, to actively engage in the discussions.  Joint sessions with other working groups will be arranged based on relevant contributions and shared interests.