arXiv subjects

Erik Adli

Publications and source records attributed to Erik Adli.

23 records · Page 2Linked to original sources

arXiv2019

Electron bunch generation from a plasma photocathode

Plasma waves generated in the wake of intense, relativistic laser or particle beams can accelerate electron bunches to giga-electronvolt (GeV) energies in centimetre-scale distances. This allows the realization of compact accelerators having emerging applications, ranging from modern light sources such as the free-electron laser (FEL) to energy frontier lepton colliders. In a plasma wakefield accelerator, such multi-gigavolt-per-metre (GV m$^{-1}$) wakefields can accelerate witness electron bunches that are either externally injected or captured from the background plasma. Here we demonstrate optically triggered injection and acceleration of electron bunches, generated in a multi-component hydrogen and helium plasma employing a spatially aligned and synchronized laser pulse. This ''plasma photocathode'' decouples injection from wake excitation by liberating tunnel-ionized helium electrons directly inside the plasma cavity, where these cold electrons are then rapidly boosted to relativistic velocities. The injection regime can be accessed via optical density down-ramp injection, is highly tunable and paves the way to generation of electron beams with unprecedented low transverse emittance, high current and 6D-brightness. This experimental path opens numerous prospects for transformative plasma wakefield accelerator applications based on ultra-high brightness beams.

physics.acc-ph↗

arXiv2019

Plasma Wakefield Linear Colliders - Opportunities and Challenges

A linear electron-positron collider operating at TeV scale energies will provide high precision measurements and allow, for example, precision studies of the Higgs boson as well as searches for physics beyond the standard model. A future linear collider should produce collisions at high energy, with high luminosity and with a good wall plug to beam power transfer efficiency. The luminosity per power consumed is a key metric that can be used to compare linear collider concepts. The plasma wakefield accelerator has demonstrated high-gradient, high-efficiency acceleration of an electron beam, and is therefore a promising technology for a future linear collider. We will go through the opportunities of using plasma wakefield acceleration technology for a collider, as well as a few of the collider-specific challenges that must be addressed in order for a high-energy, high luminosity-per-power plasma wakefield collider to become a reality.

physics.acc-ph↗

arXiv2018

Analytic plasma wakefield limits for active plasma lenses

Active plasma lensing is a promising technology for compact focusing of particle beams that has seen a recent surge of interest. While these lenses can provide strong focusing gradients of order kT/m and focusing in both transverse planes, there are limitations from nonlinear aberrations, causing emittance growth in the beams being focused. One cause of such aberrations is beam-driven plasma wakefields, present if the beam density is sufficiently high. We develop simple, but powerful analytic formulas for the effective focusing gradient from these wakefields, and use this to set limits on which parts of the beam and plasma parameter space permits distortion-free use of active plasma lenses. It is concluded that the application of active plasma lenses to conventional and plasma-based linear colliders may prove very challenging, except perhaps in the final focus system, unless the typical discharge currents used are dramatically increased, and that in general these lenses are better suited for accelerator applications with lower beam intensities.

physics.acc-ph↗

arXiv2017

Emittance preservation of an electron beam in a loaded quasi-linear plasma wakefield

We investigate beam loading and emittance preservation for a high-charge electron beam being accelerated in quasi-linear plasma wakefields driven by a short proton beam. The structure of the studied wakefields are similar to those of a long, modulated proton beam, such as the AWAKE proton driver. We show that by properly choosing the electron beam parameters and exploiting two well known effects, beam loading of the wakefield and full blow out of plasma electrons by the accelerated beam, the electron beam can gain large amounts of energy with a narrow final energy spread (%-level) and without significant emittance growth.

physics.acc-ph↗

arXiv2013

A Beam Driven Plasma-Wakefield Linear Collider: From Higgs Factory to Multi-TeV

Plasma wakefield acceleration (PWFA) holds much promise for advancing the energy frontier because it can potentially provide a 1000-fold or more increase in acceleration gradient with excellent power efficiency in respect with standard technologies. Most of the advances in beam-driven plasma wakefield acceleration were obtained by a UCLA/USC/SLAC collaboration working at the SLAC FFTB[ ]. These experiments have shown that plasmas can accelerate and focus both electron and positron high energy beams, and an accelerating gradient in excess of 50 GeV/m can be sustained in an 85 cm-long plasma. The FFTB experiments were essentially proof-of-principle experiments that showed the great potential of plasma accelerators. The FACET[ ] test facility at SLAC will in the period 2012-2016 further study several issues that are directly related to the applicability of PWFA to a high-energy collider, in particular two-beam acceleration where the witness beam experiences high beam loading (required for high efficiency), small energy spread and small emittance dilution (required to achieve luminosity). The PWFA-LC concept presented in this document is an attempt to find the best design that takes advantage of the PWFA, identify the critical parameters to be achieved and eventually the necessary R&D to address their feasibility. It best benefits from the extensive R&D that has been performed for conventional rf linear colliders during the last twenty years, especially ILC[ ] and CLIC[ ], with a potential for a comparably lower power consumption and cost.

physics.acc-ph↗