Discussion round:

Simulations for very high energy stages

​

ALEGRO 2025

Facility for Advanced Accelerator Experimental Tests

Why this discussion matters

classic PWFA challenges

​

• Positron acceleration
• Wall-plug efficiency
• Beam-quality preservation
• Repetition rate and average power
• Space-efficient staging
• Stability (e.g. hosing)
• Drive-beam coupling�

Why this discussion matters

“Low-energy” regime

classic PWFA challenges

“High-energy” regime

​

• Positron acceleration
• Wall-plug efficiency
• Beam-quality preservation
• Repetition rate and average power
• Space-efficient staging
• Stability (e.g. hosing)
• Drive-beam coupling

Are we equipped to model the largest part of the PWFA LINAC ?

• Synchrotron radiation in magnets
• Betatron radiation
• Secondaries (e.g. pair production)
• High-density witness bunches
• Ion motion
• Polarization
• Interstage length grow with trailing-beam energy

​

​

​

Discussion points

​

• Do we have a complete understanding of physics relevant in high-energy stages ?

​

• Can full PIC codes describe all relevant physics of high-energy plasma stages ?

​

• Does the hand-shaking between PIC and beam-transport codes work seamlessly ?

​

• Simulating 100s of stages can become computationally expensive. What is the best strategy to accelerate these simulations ?

​

• Can we scale current staging concepts into the high-energy regime ? Quadrupoles are too weak, do ramps become too expensive ?

​

• Is internal injection relevant for high-energy stages ?

​

​

​

​

​

​

​

​

​

​

​

​

Physics in High energy PWFAs

Trailing-beam transport between stages and drive-beam coupling

• Well-functioning handshakes between PIC and beam-dynamic code
• ISR and CSR
• Space-charge
• Polarization

​

​

Plasma-accelerator modeling

• High-density trailing beams
• Ion motion
• Polarization
• Radiation reaction betatron radiation

​

​