20th Advanced Accelerator Concepts Workshop

6 Nov 2022, 15:00 → 11 Nov 2022, 17:10 America/New_York

Hyatt Regency Long Island

Mark Palmer (Brookhaven National Laboratory) , Navid Vafaei-Najafabadi (Stony Brook University)

The AAC’22 workshop is the 20th in a series of by-invitation biennial fora for intensive discussions on long-term research in advanced accelerator physics and technology. This research supports the development of capabilities for the basic sciences, from photon science to high energy physics, as well as the development of compact accelerators for industrial, medical and security applications.

AAC'22 will be organized into eight working groups covering the following topical areas:

1. Laser-Plasma Wakefield Acceleration 
2. Computation for Accelerator Physics
3. Laser and High-Gradient Structure-Based Acceleration
4. Beam-Driven Acceleration
5. Beam Sources, Monitoring, and Control
6. Laser-Plasma Acceleration of Ions
7. Radiation Generation and Advanced Concepts
8. Advanced Laser and Beam Technology and Facilities

Conference Home:  https://www.aac2022.org/

 

Sunday, 6 November

18:00 → 19:30 Welcome Reception

Monday, 7 November

10:20 → 10:40 Coffee Break

12:10 → 13:30 Lunch

15:00 → 15:30 Coffee Break

Tuesday, 8 November

10:00 → 10:30 Coffee Break

12:00 → 13:20 Lunch

15:00 → 15:30 Coffee Break/Exhibits

15:30 → 17:00 WGs 2+8 Joint Session: Session 1 of 1

Joint session between working groups 2 & 8:
WG2 - Computation for Accelerator Physics
WG8 - Advanced Laser and Beam Technology and Facilities

Conveners: Alexey Arefiev (UC San Diego) , David Bruhwiler (RadiaSoft LLC) , Mr Marcus Babzien (BNL) , Stephen Milton

15:30 Thermal Modeling and Benchmarking of Crystalline Laser Amplifiers

Detailed thermal modeling of crystal amplifiers is a prerequisite for rapid improvement—higher pulse quality, higher average power at maximum achievable peak intensity, better repeatability, etc.—of high-intensity lasers ($100~\mathrm{TW}$ to multi-PW) with ultra-short pulse lengths ($< 100~\mathrm{fs}$). In recent work [1], we used the open-source, finite-element code FEniCS [2] to solve the linear partial differential equation for thermal transport across a cylindrical Ti:Sapphire crystal, assuming a $532~\mathrm{nm}$ Gaussian pump laser illuminating the crystal from one side at $1~\mathrm{kHz}$. From the experimentally measured thermal time scale of approximately $150~\mathrm{ms}$, we inferred a room-temperature thermal diffusivity of about $0.29~\mathrm{cm}^2/\mathrm{s}$. This value does not agree well with those calculated directly from thermal conductivity and specific heat capacity values found in the literature. Sources of uncertainty include (a) the pump laser power absorbed as heat by the crystal (which depends on both the absorption coefficient and the fractional thermal heat load), and (b) variations of the thermal conductivity and specific heat capacity (which vary with both temperature and details of the titanium doping). In order to address these uncertainties, we have generalized our FEniCS model to include nonlinearities associated with temperature variations of the thermal conductivity and specific heat capacity, across a wide range of temperatures. We will present recent work, comparing linear and nonlinear simulations, at cryogenic temperatures and also at room temperature.

[1] D.T. Abell et al., Proc. IPAC’22, THPOTK062, https://jacow.org/ipac2022/papers/thpotk062.pdf.
[2] The FEniCS Computing Platform, https://fenicsproject.org.

Speaker: Dr Dan Abell (RadiaSoft LLC)

20221110_Abell_AAC.pdf

15:50 Efficient propagation of electromagnetic pulses through high-power solid state laser amplifiers

There is currently a lack of broadly available modeling software that self-consistently captures the required physics of gain, thermal loading and lensing, spectral shaping, and other effects required to simulate and optimize high-intensity lasers (100 TW to multi-PW) with ultra-short pulse lengths (< 100 fs) [1]. In recent work [2], we showed that low-resolution wavefront sensor (WFS) images could be used to construct native SRW [3] wavefront objects. We propagate these general 2D wavefronts via linear canonical transforms (LCT) [4], using the decomposition of Pei and Huang [5] to recast a standard ABCD matrix into three, each of which SRW can use to transform the wavefront with physical optics. We present an operator splitting approach, which divides both the crystal and the amplified laser pulse into slices, so that the algorithms remain 2D for an intrinsically 3D problem. We also discuss work on a new Python library for LCTs, which will enable wavefront propagation via more general ABCD matrices. Comparisons with experimental data are presented.

[1] R. Falcone et al., Brightest Light Initiative Workshop Report: the Future of Intense Ultrafast Lasers in the U.S. (2020), doi:10.2172/1604161

[2] D.L. Bruhwiler et al., “Open source software to simulate Ti:Sapphire amplifiers,” in Proc. Int. Part. Accel. Conf., THPOTK063 (2022); https://accelconf.web.cern.ch/ipac2022/papers/thpotk063.pdf

[3] O. Chubar, Synchrotron Radiation Workshop (SRW), https://github.com/ochubar/srw

[4] J. Healy, M. Kutay, H. Ozaktas, and J. Sheridan, Linear Canonical Transforms: Theory and Applications (2016), doi:10.1007/978-1-4939-3028-9

[5] S.-C. Pei and S.-G. Huang, “Two-dimensional nonseparable discrete linear canonical transform based on cm-cc-cm-cc decomposition,” J. Opt. Soc. Am. A 33, p. 214 (2016), doi:10.1364/JOSAA.33.000214

Speaker: Dr David Bruhwiler (RadiaSoft LLC)

20221108_Bruhwiler_LaserModeling_AAC.pdf

16:10 Discussion

Wednesday, 9 November

10:00 → 10:30 Coffee Break/Exhibits

12:00 → 13:20 Lunch

Thursday, 10 November

10:00 → 10:30 Coffee Break/Exhibits

12:00 → 13:20 Lunch

15:00 → 18:00 Afternoon at Leisure

Friday, 11 November

10:00 → 10:30 Coffee Break

12:00 → 13:00 Lunch

14:40 → 15:00 Coffee Break