Nonlinear plasma wavelength scalings in a laser wakefield accelerator

Ding, Hao; Döpp, A.; Gilljohann, Max; Götzfried, Johannes; Schindler, S.; Wildgruber, L.; Cheung, Gemmy; Hooker, S. M.; Karsch, Stefan

doi:10.1103/physreve.101.023209

Cited by 12 publications

(9 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Note that beam loading in this regime is actually entirely determined by the beam current, which is proportional to the beam charge for a given bunch duration [50]. Most experiments, however, operate in an intermediary regime between perturbation and blow out, which currently lacks a consistent theoretical description [52]. To nevertheless illustrate the interplay between both laser and particle beams which is central to this work, we use self-consistent particle-in-cell simulations [53].…”

Section: Introductionmentioning

confidence: 99%

Physics of High-Charge Electron Beams in Laser-Plasma Wakefields

et al. 2020

Self Cite

View full text Add to dashboard Cite

Laser wakefield acceleration (LWFA) and its particle-driven counterpart, particle or plasma wakefield acceleration (PWFA), are commonly treated as separate, though related, branches of high-gradient plasmabased acceleration. However, novel proposed schemes are increasingly residing at the interface of both concepts where the understanding of their interplay becomes crucial. Here, we present a comprehensive study of this regime, which we may term laser-plasma wakefields. Using datasets of hundreds of shots, we demonstrate the influence of beam loading on the spectral shape of electron bunches. Similar results are obtained using both 100-TW-class and few-cycle lasers, highlighting the scale invariance of the involved physical processes. Furthermore, we probe the interplay of dual electron bunches in the same or in two subsequent plasma periods under the influence of beam loading. We show that, with decreasing laser intensity, beam loading transitions to a beam-dominated regime, where the first bunch acts as the main driver of the wakefield. This transition is evidenced experimentally by a varying acceleration of a lowenergy witness beam with respect to the charge of a high-energy drive beam in a spatially separate gas target. Our results also present an important step in the development of LWFA using controlled injection in a shock front. The electron beams in this study reach record performance in terms of laser-to-beam energy transfer efficiency (up to 10%), spectral charge density (regularly exceeding 10 pC MeV −1), and angular charge density (beyond 300 pC μsr −1 at 220 MeV). We provide an experimental scaling for the accelerated charge per terawatt (TW) of laser power, which approaches 2 nC at 300 TW. With the expanding availability of petawatt-class (PW) lasers, these beam parameters will become widely accessible. Thus, the physics of laser-plasma wakefields is expected to become increasingly relevant, as it provides new paths toward low-emittance beam generation for future plasma-based colliders or light sources.

show abstract

Section: Introductionmentioning

confidence: 99%

Physics of High-Charge Electron Beams in Laser-Plasma Wakefields

et al. 2020

Self Cite

View full text Add to dashboard Cite

show abstract

“…A hybrid plasma accelerator utilizes the dense, high-current electron bunch produced by a laser-wakefield accelerator to drive the plasma wave for a plasma-wakefield acceleration (PWFA) [19,28,29] . Unlike in PWFA driven by electron bunches from conventional radio frequency (RF) accelerators, the plasma density in a hybrid accelerator is higher, typically approximately 10 18 cm −3 , which makes it possible for shadowgraphy using few-cycle optical probes [18][19][20] . The plasma evolution can be observed in detail in femtosecond resolution using a fewcycle probe beam.…”

Section: Few-cycle Shadowgraphy Of Plasma Wavesmentioning

confidence: 99%

“…In particular, the evolving structure of a plasma accelerator is challenging to visualize because of its microscopic size (∼10 −5 m) and its high velocity (approaching the speed of light). With the latest techniques, such as few-cycle shadowgraphy, taking snapshots of the plasma wake structure is enabled in femtosecond resolution over a range of picoseconds [18][19][20] . The latest generation of laboratory diagnostics for plasma structures is reviewed by Downer et al [21] .…”

Section: Introductionmentioning

confidence: 99%

Applications of object detection networks in high-power laser systems and experiments

Lin

Haberstroh²,

Karsch³

et al. 2023

High Pow Laser Sci Eng

View full text Add to dashboard Cite

The recent advent of deep artificial neural networks has resulted in a dramatic increase in performance for object classification and detection. While pre-trained with everyday objects, we find that a state-of-the-art object detection architecture can very efficiently be fine-tuned to work on a variety of object detection tasks in a high-power laser laboratory. In this manuscript, three exemplary applications are presented. We show that the plasma waves in a laserplasma accelerator can be detected and located on the optical shadowgrams. The plasma wavelength and plasma density are estimated accordingly. Furthermore, we present the detection of all the peaks in an electron energy spectrum of the accelerated electron beam, and the beam charge of each peak is estimated accordingly. Lastly, we demonstrate the detection of optical damage in a high-power laser system. The reliability of the object detector is demonstrated over one thousand laser shots in each application. Our study shows that deep object detection networks are suitable to assist online and offline experiment analysis, even with small training sets. We believe that the presented methodology is adaptable yet robust, and we encourage further applications in Hz-level or KHz-level high-power laser facilities regarding the control and diagnostic tools, especially for those involving image data.

show abstract

“…2002; Ding et al. 2020), the accelerators will typically operate at plasma densities of or lower, resulting in dephasing limited beam energies above 100 MeV (Döpp et al. 2016).…”

Section: Introductionmentioning

confidence: 99%

All-optical Compton scattering at shallow interaction angles

Döpp,

Ta Phuoc,

Andriyash

2023

J. Plasma Phys.

View full text Add to dashboard Cite

All-optical Compton sources combine laser-wakefield accelerators and intense scattering pulses to generate ultrashort bursts of backscattered radiation. The scattering pulse plays the role of a small-period undulator ( ${\sim }1\,\mathrm {\mu }{\rm m}$ ) in which relativistic electrons oscillate and emit X-ray radiation. To date, most of the working laser-plasma accelerators operate preferably at energies of a few hundreds of megaelectronvolts and the Compton sources developed so far produce radiation in the range from hundreds of kiloelectronvolts to a few megaelectronvolts. However, for such applications as medical imaging and tomography the relevant energy range is 10–100 keV. In this article, we discuss different scattering geometries for the generation of X-rays in this range. Through numerical simulations, we study the influence of electron beam parameters on the backscattered photons. We find that the spectral bandwidth remains constant for beams of the same emittance regardless of the scattering geometry. A shallow interaction angle of $30^{\circ }$ or less seems particularly promising for imaging applications given parameters of existing laser-plasma accelerators. Finally, we discuss the influence of the radiation properties for potential applications in medical imaging and non-destructive testing.

show abstract

Nonlinear plasma wavelength scalings in a laser wakefield accelerator

Cited by 12 publications

References 40 publications

Physics of High-Charge Electron Beams in Laser-Plasma Wakefields

Physics of High-Charge Electron Beams in Laser-Plasma Wakefields

Applications of object detection networks in high-power laser systems and experiments

All-optical Compton scattering at shallow interaction angles

Contact Info

Product

Resources

About