# Publications by Laura Corner

## Meter-scale conditioned hydrodynamic optical-field-ionized plasma channels

Physical Review E American Physical Society 102 (2020) 53201

A Picksley, A Alejo, R Shalloo, C Arran, A von Boetticher, L Corner, J Holloway, J Jonnerby, O Jakobsson, C Thornton, R Walczak, S Hooker

We demonstrate through experiments and numerical simulations that low-density, low-loss, meter-scale plasma channels can be generated by employing a conditioning laser pulse to ionize the neutral gas collar surrounding a hydrodynamic optical-field-ionized (HOFI) plasma channel. We use particle-in-cell simulations to show that the leading edge of the conditioning pulse ionizes the neutral gas collar to generate a deep, low-loss plasma channel which guides the bulk of the conditioning pulse itself as well as any subsequently injected pulses. In proof-of-principle experiments, we generate conditioned HOFI (CHOFI) waveguides with axial electron densities of ne0≈1×10^17cm−3 and a matched spot size of 26μm. The power attenuation length of these CHOFI channels was calculated to be Latt=(21±3)m, more than two orders of magnitude longer than achieved by HOFI channels. Hydrodynamic and particle-in-cell simulations demonstrate that meter-scale CHOFI waveguides with attenuation lengths exceeding 1 m could be generated with a total laser pulse energy of only 1.2 J per meter of channel. The properties of CHOFI channels are ideally suited to many applications in high-intensity light-matter interactions, including multi-GeV plasma accelerator stages operating at high pulse repetition rates.

## Guiding of high-intensity laser pulses in 100mm-long hydrodynamic optical-field-ionized plasma channels

Physical Review Accelerators and Beams American Physical Society 23 (2020) 081303

A Picksley, A Alejo, J Cowley, N Bourgeois, L Corner, L Feder, J Holloway, H Jones, J Jonnerby, H Milchberg, L Reid, A Ross, R Walczak, S Hooker

Hydrodynamic optically-field-ionized (HOFI) plasma channels up to 100mm long are investigated. Optical guiding is demonstrated of laser pulses with a peak input intensity of $6\times10^{17}$ W cm$^{-2}$ through 100mm long plasma channels with on-axis densities measured interferometrically to be as low as $n_{e0} =(1.0\pm0.3)\times10^{17}$cm$^{-3}$. Guiding is also observed at lower axial densities, which are inferred from magneto-hydrodynamic simulations to be approximately $7\times10^{16}$cm$^{-3}$. Measurements of the power attenuation lengths of the channels are shown to be in good agreement with those calculated from the measured transverse electron density profiles. To our knowledge, the plasma channels investigated in this work are the longest, and have the lowest on-axis density, of any free-standing waveguide demonstrated to guide laser pulses with intensities above $&gt;10^{17}$ W cm$^{-2}$.

## Low-density hydrodynamic optical-field-ionized plasma channels generated with an axicon lens

Physical Review Accelerators and Beams American Physical Society 22 (2019) 041302-

RJ Shalloo, C Arran, A Picksley, A Von Boetticher, L Corner, J Holloway, G Hine, J Jonnerby, HM Milchberg, C Thornton, R Walczak, S Hooker

We demonstrate optical guiding of high-intensity laser pulses in long, low density hydrodynamic optical-field-ionized (HOFI) plasma channels. An axicon lens is used to generate HOFI plasma channels with on-axis electron densities as low as $n_e(0) = 1.5\times 10^{17}\, \mathrm{cm}^{-3}$ and matched spot sizes in the range $20 \mu \mathrm{m} \lesssim W_M \lesssim 40 \mu \mathrm{m}$. Control of these channel parameters via adjustment of the initial cell pressure and the delay after the arrival of the channel-forming pulse is demonstrated. For laser pulses with a peak axial intensity of $4 \times 10^{17}\, \mathrm{W\,cm}^{-2}$, highly reproducible, high-quality guiding over more than 14 Rayleigh ranges is achieved at a pulse repetition rate of 5 Hz, limited by the available channel-forming laser and vacuum pumping system. Plasma channels of this type would seem to be well suited to multi-GeV laser wakefield accelerators operating in the quasi-linear regime.

## Hydrodynamic optical-field-ionized plasma channels

Physical Review E American Physical Society 97 (2018) 053203

RJ Shalloo, C Arran, L Corner, J Holloway, J Jonnerby, R Walczak, HM Milchberg, S Hooker

We present experiments and numerical simulations which demonstrate that fully-ionized, lowdensity plasma channels could be formed by hydrodynamic expansion of plasma columns produced by optical field ionization (OFI). Simulations of the hydrodynamic expansion of plasma columns formed in hydrogen by an axicon lens show the generation of 200 mm long plasma channels with axial densities of order ne(0) = 1 × 1017 cm−3 and lowest-order modes of spot size WM ≈ 40 µm. These simulations show that the laser energy required to generate the channels is modest: of order 1 mJ per centimetre of channel. The simulations are confirmed by experiments with a spherical lens which show the formation of short plasma channels with 1.5 × 1017 cm−3 . ne(0) . 1 × 1018 cm−3 and 61 µm &amp; WM &amp; 33 µm. Low-density plasma channels of this type would appear to be well-suited as multi-GeV laser-plasma accelerator stages capable of long-term operation at high pulse repetition rates.

## Excitation and control of plasma wakefields by multiple laser pulses

Physical Review Letters American Physical Society 119 (2017) 044802-

J Cowley, C Thornton, CD Arran, RJ Shalloo, L Corner, G Cheung, CD Gregory, SPD Mangles, NH Matlis, Symes, R Walczak, SM Hooker

We demonstrate experimentally the resonant excitation of plasma waves by trains of laser pulses. We also take an important first step to achieving an energy recovery plasma accelerator by showing that unused wakefield energy can be removed by an out-of-resonance trailing laser pulse. The measured laser wakefields are found to be in excellent agreement with analytical and numerical models of wakefield excitation in the linear regime. Our results indicate a promising direction for achieving highly controlled, GeV-scale laser-plasma accelerators operating at multi-kilohertz repetition rates.

## The Coherent Combination of Fibre Lasers - Towards Realistic Applications

P Tudor, L Corner, R Walczak, AIP

## Secondary wavelength stabilization of unbalanced Michelson interferometers for the generation of low-jitter pulse trains

Optics Letters Optical Society of America 41 (2016) 4068-4070

L Corner, RJ Shalloo

We present a double unbalanced Michelson interferometer producing up to 4 output pulses from a single input pulse. The interferometer is stabilized with the Hänsch-Couillard method using an auxiliary low power continuous wave laser injected into the interferometer, allowing the stabilization of the temporal jitter of the output pulses to 0.02fs. Such stabilized pulse trains would be suitable for driving multi-pulse laser wakefield accelerators and the technique could be extended to include amplification in the arms of the interferometer.

## Generation of laser pulse trains for tests of multi-pulse laser wakefield acceleration

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment Elsevier 829 (2016) 383-385

R Shalloo, L Corner, C Arran, J Cowley, G Cheung, C Thornton, R Walczak, SM Hooker

In multi-pulse laser wakefield acceleration (MP-LWFA) a plasma wave is driven by a train of low-energy laser pulses separated by the plasma period, an approach which offers a route to driving plasma accelerators with high efficiency and at high pulse repetition rates using emerging technologies such as fibre and thin-disk lasers. Whilst these laser technologies are in development, proof-of-principle tests of MP-LWFA require a pulse train to be generated from a single, high-energy ultrafast pulse. Here we demonstrate the generation of trains of up to 7 pulses with pulse separations in the range 150–170 fs from single 40 fs pulses produced by a Ti:sapphire laser.

## Generation of laser pulse trains for tests of multi-pulse laser wakefield acceleration

Nuclear Instruments and Methods in Physics Research A Elsevier 829 (2016) 383-385

S Hooker, L Corner, C Arran, J Cowley, G Cheung, C Thornton, R Walczak

In multi-pulse laser wakefield acceleration (MP-LWFA) a plasma wave is driven by a train of low-energy laser pulses separated by the plasma period, an approach which offers a route to driving plasma accelerators with high efficiency and at high pulse repetition rates using emerging technologies such as fibre and thin-disk lasers. Whilst these laser technologies are in development, proof-of-principle tests of MP-LWFA require a pulse train to be generated from a single, high-energy ultrafast pulse. Here we demonstrate the generation of trains of up to 7 pulses with pulse separations in the range 150–170 fs from single 40 fs pulses produced by a Ti:sapphire laser.

## Multi-pulse laser wakefield acceleration: a new route to efficient, high-repetition-rate plasma accelerators and high flux radiation sources

JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS 47 (2014) ARTN 234003

SM Hooker, R Bartolini, SPD Mangles, A Tuennermann, L Corner, J Limpert, A Seryi, R Walczak

## Laserwire at the Accelerator Test Facility 2 with submicrometer resolution

PHYSICAL REVIEW SPECIAL TOPICS-ACCELERATORS AND BEAMS 17 (2014) ARTN 072802

LJ Nevay, ST Boogert, P Karataev, K Kruchinin, L Corner, DF Howell, R Walczak, A Aryshev, J Urakawa, N Terunuma

## High power fiber laser system for a high repetition rate laserwire

PHYSICAL REVIEW SPECIAL TOPICS-ACCELERATORS AND BEAMS 17 (2014) ARTN 072801

LJ Nevay, R Walczak, L Corner

## Fibre lasers for gamma colliders

EUROPEAN PHYSICAL JOURNAL-SPECIAL TOPICS 223 (2014) 1207-1211

L Corner

## Laserwire: A high resolution non-invasive beam profiling diagnostic

Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment (2013)

L Corner, R Walczak, A Aryshev, N Terunuma, J Urakawa, GA Blair, ST Boogert, P Karataev, K Kruchinin, LJ Nevay

A laserwire is a non-invasive, high resolution particle beam size monitor based on Compton scattering that is required for future planned colliders and can also be used to estimate the size of the source in wakefield acceleration experiments. We present recent results from the high resolution laserwire transverse electron beam diagnostic installed at the Accelerator Test Facility 2 (ATF2) electron accelerator at KEK in Japan. Full characterisation of the propagation of the 150 mJ, 77 ps laser beam is used to deconvolve the transverse laserwire profile demonstrating the successful measurement of 1 μm scale vertical electron beam sizes, even with extreme aspect ratios. We also present progress in the development of high energy photonic crystal fibre based laser systems for laserwire measurements at megahertz repetition rates, suitable for intra-train scanning for planned accelerators such as the International Linear Collider, or beam size measurement in laser or particle driven plasma accelerators. © 2013 Elsevier B.V. All rights reserved.

## Laserwire: A high resolution non-invasive beam profiling diagnostic

Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 740 (2014) 226-228

L Corner, A Aryshev, GA Blair, ST Boogert, P Karataev, K Kruchinin, LJ Nevay, N Terunuma, J Urakawa, R Walczak

A laserwire is a non-invasive, high resolution particle beam size monitor based on Compton scattering that is required for future planned colliders and can also be used to estimate the size of the source in wakefield acceleration experiments. We present recent results from the high resolution laserwire transverse electron beam diagnostic installed at the Accelerator Test Facility 2 (ATF2) electron accelerator at KEK in Japan. Full characterisation of the propagation of the 150 mJ, 77 ps laser beam is used to deconvolve the transverse laserwire profile demonstrating the successful measurement of 1 μm scale vertical electron beam sizes, even with extreme aspect ratios. We also present progress in the development of high energy photonic crystal fibre based laser systems for laserwire measurements at megahertz repetition rates, suitable for intra-train scanning for planned accelerators such as the International Linear Collider, or beam size measurement in laser or particle driven plasma accelerators. © 2013 Elsevier B.V.

## Experimental validation of a novel compact focusing scheme for future energy-frontier linear lepton colliders.

Phys Rev Lett 112 (2014) 034802-

GR White, R Ainsworth, T Akagi, J Alabau-Gonzalvo, D Angal-Kalinin, S Araki, A Aryshev, S Bai, P Bambade, DR Bett, G Blair, C Blanch, O Blanco, N Blaskovic-Kraljevic, B Bolzon, S Boogert, PN Burrows, G Christian, L Corner, MR Davis, A Faus-Golfe, M Fukuda, J Gao, H García-Morales, N Geffroy, H Hayano, AY Heo, M Hildreth, Y Honda, JY Huang, WH Hwang, Y Iwashita, S Jang, A Jeremie, Y Kamiya, P Karataev, ES Kim, HS Kim, SH Kim, YI Kim, S Komamiya, K Kubo, T Kume, S Kuroda, B Lam, K Lekomtsev, S Liu, A Lyapin, E Marin, M Masuzawa, D McCormick, T Naito, J Nelson, LJ Nevay, T Okugi, T Omori, M Oroku, H Park, YJ Park, C Perry, J Pfingstner, N Phinney, A Rawankar, Y Renier, J Resta-López, M Ross, T Sanuki, D Schulte, A Seryi, M Shevelev, H Shimizu, J Snuverink, C Spencer, T Suehara, R Sugahara, T Takahashi, R Tanaka, T Tauchi, N Terunuma, R Tomás, J Urakawa, D Wang, M Warden, M Wendt, A Wolski, M Woodley, Y Yamaguchi, T Yamanaka, J Yan, K Yokoya, F Zimmermann, ATF2 Collaboration

A novel scheme for the focusing of high-energy leptons in future linear colliders was proposed in 2001 [P. Raimondi and A. Seryi, Phys. Rev. Lett. 86, 3779 (2001)]. This scheme has many advantageous properties over previously studied focusing schemes, including being significantly shorter for a given energy and having a significantly better energy bandwidth. Experimental results from the ATF2 accelerator at KEK are presented that validate the operating principle of such a scheme by demonstrating the demagnification of a 1.3 GeV electron beam down to below 65 nm in height using an energy-scaled version of the compact focusing optics designed for the ILC collider.

## Status of the CLIC-UK R&amp;D programme on design of key systems for the compact linear collider

IPAC 2014: Proceedings of the 5th International Particle Accelerator Conference (2014) 1354-1357

JA Clarke, N Collomb, SP Jamison, PA McIntosh, BJA Shepherd, G Stokes, R Corsini, A Grudiev, A Latina, T Lefevre, C Marrelli, M Modena, H Schmickler, D Schulte, P Skowronski, S Stapnes, F Tecker, R Tomas, R Wegner, M Wendt, W Wuensch, WA Gillespie, R Pan, MA Tyrk, DA Walsh, DR Bett, N Blaskovic Kraljevic, PN Burrows, GB Christian, L Corner, MR Davis, D Gamba, C Perry, J Roberts, R Ainsworth, T Aumeyr, L Bobb, S Boogert, A Bosco, FJ Cullinan, P Karataev, K Kruchinin, A Lyapin, LJ Nevay, J Snuverink, JR Towler, G Burt, A Dexter, M Jenkins, S Karimian, C Lingwood, B Woolley, R Jones, AV Praveen Kumar

Copyright © 2014 CC-BY-3.0 and by the respective authors. Six UK institutes are engaged in a collaborative R&D programme with CERN aimed at demonstrating key aspects of technology feasibility for the Compact Linear Collider (CLIC). We give an overview and status of: 1) Drive-beam components: quadrupole magnets and the beam phase feed-forward prototype. 2) Beam instrumentation: stripline and cavity beam position monitors, an electro-optical longitudinal bunch profile monitor, and laserwire and diffraction and transition radiation monitors for transverse beam-size determination. 3) Beam delivery system and machinedetector interface design, including beam feedback/control systems and crab cavity design and control. 4) RF structure design. In each case we report on the status of prototype systems and performance tests with beam at the CTF3, ATF2 and CESRTA test facilities, including plans for future experiments.

## Sub-micrometre resolution laser wire transverse beam size measurement system

IPAC 2013: Proceedings of the 4th International Particle Accelerator Conference (2013) 795-797

LJ Nevay, GA Blair, ST Boogert, P Karataev, K Krunchinin, L Corner, R Walczak, A Aryshev, J Urakawa, N Terunuma

We present the results from the laserwire system at the Accelerator Test Facility 2 (ATF2) during recent operation after relocation to the virtual image point of the ATF2 final focus. The characterisation of the 150 mJ, 77 ps long laser pulses at a scaled virtual interaction point is used to deconvolve the transverse laserwire profile demonstrating a 1.16 ± 0.06 μm vertical electron beam profile. Horizontal laserwire scans were used in combination with the vertical scans to measure the electron beam size using a full overlap integral model due to the problems presented by a large aspect ratio electron beam. Copyright © 2013 by JACoW.

## Sub-micrometre resolution laserwire transverse beam size measurement system

IBIC 2013: Proceedings of the 2nd International Beam Instrumentation Conference (2013) 243-246

LJ Nevay, ST Boogert, P Karataev, K Kruchinin, L Corner, R Walczak, A Aryshev, J Urakawa, N Terunuma

Copyright © 2013 by JACoW. The laserwire system at the Accelerator Test Facility 2 (ATF2) is a transverse beam profile measurement system capable of measuring a micrometre-size electron beam. We present recent results demonstrating a measured vertical size of 1.16 ± 0.06 μm and a horizontal size of 110.1 ± 3.8 μ m. Due to the high aspect ratio of the electron beam, the natural divergence of the tightly focussed laser beam across the electron beam width requires the use of the full overlap integral to deconvolve the scans. For this to be done accurately, the propagation of the 150 mJ, 167 ps long laser pulses was precisely measured at a scaled virtual interaction point.

## Multiple pulse resonantly enhanced laser plasma wakefield acceleration

AIP Conference Proceedings 1507 (2012) 872-873

L Corner, R Walczak, LJ Nevay, S Dann, SM Hooker, N Bourgeois, J Cowley

We present an outline of experiments being conducted at Oxford University on multiple-pulse, resonantly-enhanced laser plasma wakefield acceleration. This method of laser plasma acceleration uses trains of optimally spaced low energy short pulses to drive plasma oscillations and may enable laser plasma accelerators to be driven by compact and efficient fibre laser sources operating at high repetition rates. © 2012 American Institute of Physics.