Beamstrahlung considerations in laser-plasma-accelerator-based linear colliders

C B Schroeder,W P Leemans,E Esarey

doi:10.1103/physrevstab.15.051301

C B Schroeder, W P Leemans + Show 1 more

Open Access

https://doi.org/10.1103/physrevstab.15.051301

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Abstract

Beam-beam interaction constraints modify the basic plasma density scalings for a linear collider based on laser-plasma accelerators. In the quantum beamstrahlung regime, it is shown that operating at low plasma density increases beamstrahlung effects, owing to the higher bunch charge and longer bunch length. At high plasma density, the bunch charge is limited by beam loading, and the required power is proportional to the square root of the plasma density. At low plasma density, the bunch charge is limited by beamstrahlung, which, for fixed luminosity, requires operation at higher laser repetition rate and, hence, higher power requirements, or the use of multibunch trains. If round beams are used in a multibunch train format with fixed beam loading, and the collider is constrained by beamstrahlung, then the required collider power is independent of plasma density.

Highlights

Advanced acceleration techniques are actively being pursued to expand the energy frontier of future colliders
For round beams at low plasma density, the bunch charge is limited by beamstrahlung effects
If one considers multiple bunches loaded in the plasma wave such that the total charge in the multibunch train is equal to the beam loading limit, with Mb 1⁄4 NBL=Nbeam the number of bunches, the maximum Laser-plasma accelerators (LPAs) efficiency can be recovered and the beam to plasma efficiency will be independent of plasma density

Summary

INTRODUCTION

Advanced acceleration techniques are actively being pursued to expand the energy frontier of future colliders. The reason for emphasizing this low density operating regime is that, as implied by the scaling laws derived in Ref. [6], operating at a density of 1015 cmÀ3 lowers the required collider power by an order of magnitude as compared to operating at a density of 1017 cmÀ3 (as well as lowering the accelerating field by an order of magnitude, and increasing the required laser pulse energy by 3 orders of magnitude) This scaling indicates lower densities are favorable for reduced power requirements, additional constraints may modify this basic scaling. We show how beam-beam interaction constraints, that are strongly manifest when operating at low plasma density, modify the basic plasma density scalings and, the LPA-collider design. We discuss how laser technology may influence the optimal operating regime for an LPA-based collider

BEAMSTRAHLUNG CONSIDERATIONS

PLASMA DENSITY SCALINGS

Beamstrahlung-limited regime

Collider power requirements

SUMMARY AND CONCLUSIONS