Conveners
WG1:Plasma-based accelerators and ancillary components
- Riccardo Pompili (Istituto Nazionale di Fisica Nucleare)
- Min Chen (Shanghai Jiao Tong University)
WG1:Plasma-based accelerators and ancillary components
- Riccardo Pompili (Istituto Nazionale di Fisica Nucleare)
- Min Chen (Shanghai Jiao Tong University)
WG1:Plasma-based accelerators and ancillary components
- Riccardo Pompili (Istituto Nazionale di Fisica Nucleare)
- Min Chen (Shanghai Jiao Tong University)
WG1:Plasma-based accelerators and ancillary components
- Riccardo Pompili (Istituto Nazionale di Fisica Nucleare)
- Min Chen (Shanghai Jiao Tong University)
We describe our programme to develop GeV-scale laser-driven plasma accelerators operating at pulse repetition rates in the kHz range. This is based on two novel approaches.
First is the hydrodynamic optical-field-ionized (HOFI) plasma channel. We describe the operation of HOFI channels, and demonstrate that they can guide relativistically-intense pulses through metre-scale channels with axial...
The high longitudinal electric fields generated in plasma wakefields are very attractive for a new generation of high gradient plasma based accelerators. On the other hand, the strong transverse fields increase the demand for a proper matching device in order to avoid the spoiling of beam transverse quality. A solution can be provided by the use of a plasma ramp, a region at the plasma...
The plasma-modulated plasma accelerator (P-MoPA) scheme [1, 2] provides a route for GeV-scale accelerators operating at kilohertz-repetition-rates driven by picosecond-duration laser pulses. In P-MoPa, trains of pulses are generated from a long, high-energy drive pulse via the spectral modulation caused by a low amplitude wakefield driven by a leading short, low-energy seed pulse. Our...
For plasma-wakefield accelerators to fulfil their potential for cost effectiveness and reduced environmental footprint, it is essential that their energy-transfer efficiency be maximized. A key aspect of this efficiency is the near-complete transfer of energy, or depletion, from the driver electrons to the plasma wake. Achieving full depletion is limited by the process of re-acceleration,...
In this contribution we discuss experimental results that show how plasma ion motion affects a proton drive bunch train and wakefields using the AWAKE experiment. Plasma ions move due to the ponderomotive force of transverse wakefields and lead to an average ion density decrease in the region around the axis. This, in turn, leads to a shift in the local plasma frequency, resulting in a sharp...
Plasma-based accelerators allow to boost the electron beam energy within a few centimeters. Two pioneering experiments [1,2], reporting the observation of self-amplified spontaneous emission (SASE) driven by plasma-accelerated beams, have already demonstrated their potential use for the realization of ultracompact light sources based on free-electron lasers (FELs).
However, the stochastic...
We describe a simple scheme, truncated-channel injection, to inject electrons directly into the wakefield driven by a drive pulse guided by an all-optical plasma channel. We use this approach to generate dark-current-free 1.2 GeV, 4.5% relative energy spread electron bunches with 120 TW laser pulses guided in a 110 mm-long hydrodynamic optical-field-ionized (HOFI) plasma channel. Our...
In labs worldwide, 100TW laser systems dominate systematic studies on laser-driven accelerators and secondary sources. The stable LWFA performance that has been achieved on such systems is vital for meaningful parameter studies and application-driven experiments. However, a recent upgrade of our previously highly stable 100 TW ATLAS laser system at LMU with a multi-PW capable final amplifier...
Intense laser fields interact very differently with micrometric rough surfaces than with flat objects. The interaction features high laser energy absorption and increased emission of MeV electrons, ions, and of hard x-rays.
I will report on how we revealed the underlying reason for this phenomenon by irradiating isolated, micrometric, translationally-symmetric objects by 20 TW laser pulses....
The viability of next generation TeV-class electron-positron colliders based on staging of independently-powered plasma-based accelerators relies on the possibility of accelerating high-charge bunches to high energy with high efficiency and high accelerating gradient, while maintaining a small energy spread and emittance. Achieving a small energy spread with high efficiency requires employing...
Highly polarised, high current electron bunches from compact laser-plasma accelerators are sought after for numerous application. However, current proposals to produce these beams suffer from intrinsic limitations to the reproducibility, charge, beam shape and final polarisation degree. We propose colliding pulse injection as a technique for the generation of highly polarised electron bunches...
High-brightness e-beams with duration of a few hundreds of attoseconds can be employed as direct probes, as drivers of Compton/Thomson X/γ or single-spike FEL sources. We show, by means of theory and quasi-3D-PIC simulations, that GeV scale electron beam sources having duration widely tunable in the interval 100−2000 as, with 6D brightness exceeding 10^17A/m^2/0.1% and normalized emittances...
We present a novel, compact, low-emittance positron source that is compatible with existing PWFA and LWFA facilities (https://arxiv.org/abs/2301.08368). The device is based on a Penning-Malmberg trap that collects and cools positrons. The resulting beam has low thermal emittance (less than 1 micron), but it is magnetized and the bunch length is cm-scale. We describe a method for extracting and...
The Full Energy Beam Exploitation (FEBE) beamline and experimental hutch at CLARA will combine a 250 MeV FEL quality electron beam with a 100 TW class laser and will support exploitation of the CLARA beam for advanced acceleration experiments and research. This includes plasma based and structure based acceleration, with laser and beam drivers. FEBE has been designed to provide flexibility in...
The effect of density ramps and plasma mirrors on electron beam divergence was measured in the context of staged laser wakefield acceleration. Termination of an acceleration stage was found to increase total beam divergence from 3.38 $\pm$ 0.07 mrad to 6.13 $\pm$ 0.13 mrad, and the effect was observed to persist at high energies, up to 2.2 GeV. Additionally, shot-to-shot fluctuations in...
Current Filamentation Instability (CFI) can occur in plasma wakefield accelerators as well as in astrophysical media. This instability takes place when a charged particle bunch streams through a plasma with skin depth smaller than the bunch transverse size, so that the plasma return current flows within the bunch. Repulsion between opposite currents tends to reinforce any initial transverse...
Plasma accelerators are emerging as formidable and innovative technology for the creation of table-top devices thanks to the possibility to sustain several GV/m accelerating gradients. Recently the research activity of the SPARC_LAB collaboration has been mainly devoted to heightening and stabilize the energy gain of a beam-driven plasma wakefield accelerator. Beside the upgrade of the SPARC...
Nowadays laser-plasma-based wakefield accelerators are capable to deliver GeV-level femtosecond electron bunches crucial for emerging applications in medicine, industry, and fundamental science. Many of these applications critically require the precise characterization of the accelerated electron bunch as well as the plasma wakefield that largely affects the bunch's quality. Advanced...
Despite the great advances that have been made in beam-driven plasma wakefield acceleration (PWFA) in the past decade in terms of acceleration gradient, efficiency, and beam quality preservation, so far the repetition rates of PWFAs were limited to a few Hz. In contrast, user facilities based on conventional acceleration technology routinely supply 1,000’s of bunches to 100’s of thousands (1...
Plasma wakefield acceleration revolutionized the field of particle accelerators by generating gigavolt-per-centimeter fields and paved the way toward the development of compact Free-Electron Lasers.
To achieve such large accelerations in a beam-driven plasma accelerator it is necessary to focus the driver bunch to increase its density and, at the same time, transversely match the witness the...
Development of internal injection methods in beam-driven plasma accelerators (PWFAs) is a crucial task toward high-quality low-emittance bunch generation and improved control over bunch parameters for quality-demanding applications like free-electron lasers. For this, ultrashort high peak current electron beams are required to drive a PWFA in the blowout regime which enables trapping of the...
Inter-stage distances and components in multistage PWFA concepts are among the biggest potential contributors to the total accelerator length and may strongly reduce the average gradient of a plasma based accelerator.
Here, we discuss a concept to optimize inter-plasma
distances by drive-beam coupling in the temporal domain
and gating the accelerator via a femtosecond ionization laser.
The E300 experiment at FACET-II on PWFA relies on electron and X-ray/γ-ray detectors to measure the beam dynamics and assess its matching in plasma, with the aim of preserving the beam quality, one of the most important milestone for the field. The plasma accelerator was operated in a self-ionized hydrogen plasma. The electron beam had a large enough peak current and density to trigger some...
Energy-transfer efficiency is an important quantity in plasma-wakefield acceleration, especially for applications that demand high average power. Normally, this efficiency is measured using an electron spectrometer; an invasive method that provides an energy-transfer efficiency averaged over the full length of the plasma accelerator. We present an experimental demonstration of a novel...
