Imperial College London

DrNicholasDover

Faculty of Natural SciencesDepartment of Physics

Academic Visitor
 
 
 
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Contact

 

+44 (0)20 7594 3791nicholas.dover08 Website

 
 
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Location

 

735Blackett LaboratorySouth Kensington Campus

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Summary

 

Publications

Publication Type
Year
to

39 results found

King M, Butler NMH, Wilson R, Capdessus R, Grays RJ, Powell HW, Dance RJ, Padda H, Gonzalez-Izquierdo B, Rusby DR, Dover NP, Hicks GS, Ettlinger OC, Scullion C, Carroll DC, Najmudin Z, Borghesi M, Neely D, McKenna Pet al., 2019, Role of magnetic field evolution on filamentary structure formation in intense laser-foil interactions, HIGH POWER LASER SCIENCE AND ENGINEERING, Vol: 7, ISSN: 2095-4719

Journal article

Ting A, Hafizi B, Helle M, Chen Y-H, Gordon D, Kaganovich D, Polyanskiy M, Pogorelsky I, Babzien M, Miao C, Dover N, Najmudin Z, Ettlinger Oet al., 2016, Staging and Laser Acceleration of Ions in Underdense Plasma, 17th Advanced Accelerator Concepts Workshop (AAC), Publisher: AMER INST PHYSICS, ISSN: 0094-243X

Conference paper

Chen Y-H, Helle M, Ting A, Gordon D, Dover N, Ettlinger O, Najmudin Z, Polyanskiy M, Pogorelsky I, Babzien Met al., 2016, Laser Acceleration of Protons with an Optically Shaped, Near-Critical Hydrogen Gas Target, 17th Advanced Accelerator Concepts Workshop (AAC), Publisher: AMER INST PHYSICS, ISSN: 0094-243X

Conference paper

Pogorelsky IV, Babzien M, Ben-Zvi I, Polyanskiy MN, Skaritka J, Tresca O, Dover NP, Najmudin Z, Lu W, Cook N, Ting A, Chen Y-Het al., 2016, Extending laser plasma accelerators into the mid-IR spectral domain with a next-generation ultra-fast CO2 laser, PLASMA PHYSICS AND CONTROLLED FUSION, Vol: 58, ISSN: 0741-3335

Journal article

King M, Gray RJ, Powell HW, MacLellan DA, Gonzalez-Izquierdo B, Stockhausen LC, Hicks GS, Dover NP, Rusby DR, Carroll DC, Padda H, Torres R, Kar S, Clarke RJ, Musgrave IO, Najmudin Z, Borghesi M, Neely D, McKenna Pet al., 2016, Ion acceleration and plasma jet formation in ultra-thin foils undergoing expansion and relativistic transparency, 2nd Workshop on European Advanced Accelerator Concepts (EAAC), Publisher: Elsevier, Pages: 163-166, ISSN: 0168-9002

At sufficiently high laser intensities, the rapid heating to relativistic velocities and resulting decompression of plasma electrons in an ultra-thin target foil can result in the target becoming relativistically transparent to the laser light during the interaction. Ion acceleration in this regime is strongly affected by the transition from an opaque to a relativistically transparent plasma. By spatially resolving the laser-accelerated proton beam at near-normal laser incidence and at an incidence angle of 30°, we identify characteristic features both experimentally and in particle-in-cell simulations which are consistent with the onset of three distinct ion acceleration mechanisms: sheath acceleration; radiation pressure acceleration; and transparency-enhanced acceleration. The latter mechanism occurs late in the interaction and is mediated by the formation of a plasma jet extending into the expanding ion population. The effect of laser incident angle on the plasma jet is explored.

Conference paper

Dover N, Cook N, Tresca O, Ettlinger O, Maharjan C, Polyanskiy M, Shkolnikov P, Pogorelsky I, Najmudin Zet al., 2016, Optical shaping of gas targets for laser plasma ion sources, Journal of Plasma Physics, Vol: 82, ISSN: 1469-7807

We report on the experimental demonstration of a technique to generate steep densitygradients in gas jet targets of interest to laser plasma ion acceleration. By using anintentional low energy prepulse, we generated a hydrodynamic blast wave in the gas toshape the target prior to the arrival of an intense CO2 (λ ≈ 10 µm) drive pulse. Thistechnique has been recently shown to facilitate the generation of ion beams by shockwaveacceleration (Tresca et al. 2015). Here, we discuss and introduce a model to understandthe generation of these blast waves and discuss in depth the experimental realisationof the technique, supported by hydrodynamics simulations. With appropriate prepulseenergy and timing, this blast wave can generate steepened density gradients as short asl ≈ 20 µm (1/e), opening up new possibilities for laser-plasma studies with near-criticalgaseous targets.

Journal article

Dover N, Palmer CAJ, Streeter MJV, Ahmed H, Albertazzi B, Borghesi M, Carroll DC, Fuchs J, Heathcote R, Hilz P, Kakolee KF, Kar S, Kodama R, Kon A, MacLellan DA, McKenna P, Nagel SR, Neely D, Notley MM, Nakatsutsumi M, Prasad R, Scott G, Tampo M, Zepf M, Schreiber J, Najmudin Zet al., 2016, Buffered high charge spectrally-peaked proton beams in the relativistic-transparency regime, New Journal of Physics, Vol: 18, ISSN: 1367-2630

Spectrally-peaked proton beams of high charge (Ep ≈ 8 MeV, ∆E ≈4 MeV, N ≈ 50 nC ) have been observed from the interaction of an intense laser(> 1019 Wcm−2) with ultrathin CH foils, as measured by spectrally-resolved full beamprofiles. These beams are reproducibly generated for foil thicknesses 5-100 nm, andexhibit narrowing divergence with decreasing target thickness down to ≈ 8◦for 5 nm.Simulations demonstrate that the narrow energy spread feature is a result of bufferedacceleration of protons. The radiation pressure at the front of the target results inasymmetric sheath fields which permeate throughout the target, causing preferentialforward acceleration. Due to their higher charge-to-mass ratio, the protons outrun acarbon plasma driven in the relativistic transparency regime.

Journal article

Cook N, Tresca O, Dover NP, Maharjan C, Polyanskiy MN, Najmudin Z, Shkolnikov P, Pogorelsky Iet al., 2016, Hydrodynamic Shaping of Gas Jets for Laser Driven Shock Acceleration of Helium Ions, 16th Advanced Accelerator Concepts Workshop, Publisher: AMER INST PHYSICS, ISSN: 0094-243X

Conference paper

Powell HW, King M, Gray RJ, MacLellan DA, Gonzalez-Izquierdo B, Stockhausen LC, Hicks G, Dover NP, Rusby DR, Carroll DC, Padda H, Torres R, Kar S, Clarke RJ, Musgrave IO, Najmudin Z, Borghesi M, Neely D, McKenna Pet al., 2015, Proton acceleration enhanced by a plasma jet in expanding foils undergoing relativistic transparency, New Journal of Physics, Vol: 17, ISSN: 1367-2630

Ion acceleration driven by the interaction of an ultraintense (2 × 1020 W cm−2) laser pulse with an ultrathin ($\leqslant 40$ nm) foil target is experimentally and numerically investigated. Protons accelerated by sheath fields and via laser radiation pressure are angularly separated and identified based on their directionality and signature features (e.g. transverse instabilities) in the measured spatial-intensity distribution. A low divergence, high energy proton component is also detected when the heated target electrons expand and the target becomes relativistically transparent during the interaction. 2D and 3D particle-in-cell simulations indicate that under these conditions a plasma jet is formed at the target rear, supported by a self-generated azimuthal magnetic field, which extends into the expanded layer of sheath-accelerated protons. Electrons trapped within this jet are directly accelerated to super-thermal energies by the portion of the laser pulse transmitted through the target. The resulting streaming of the electrons into the ion layers enhances the energy of protons in the vicinity of the jet. Through the addition of a controlled prepulse, the maximum energy of these protons is demonstrated experimentally and numerically to be sensitive to the picosecond rising edge profile of the laser pulse.

Journal article

Tresca O, Dover NP, Cook N, Maharjan C, Polyanskiy MN, Najmudin Z, Shkolnikov P, Pogorelsky Iet al., 2015, Spectral Modification of Shock Accelerated Ions Using a Hydrodynamically Shaped Gas Target, PHYSICAL REVIEW LETTERS, Vol: 115, ISSN: 0031-9007

Journal article

Pogorelsky IV, Ben-Zvi I, Skaritka J, Babzien M, Polyanskiy MN, Dover N, Najmudin Z, Lu Wet al., 2015, New opportunities for strong-field LPI research in the mid-IR, Conference on Relativistic Plasma Waves and Particle Beams as Coherent and Incoherent Radiation Sources, Publisher: SPIE-INT SOC OPTICAL ENGINEERING, ISSN: 0277-786X

Conference paper

Palmer CAJ, Dover NP, Pogorelsky I, Streeter MJV, Najmudin Zet al., 2015, Manipulation of laser-generated energetic proton spectra in near critical density plasma, JOURNAL OF PLASMA PHYSICS, Vol: 81, ISSN: 0022-3778

Journal article

Green JS, Dover NP, Borghesi M, Brenner CM, Cameron FH, Carroll DC, Foster PS, Gallegos P, Gregori G, McKenna P, Murphy CD, Najmudin Z, Palmer CAJ, Prasad R, Romagnani L, Quinn KE, Schreiber J, Streeter MJV, Ter-Avetisyan S, Tresca O, Zepf M, Neely Det al., 2014, Enhanced proton beam collimation in the ultra-intense short pulse regime, PLASMA PHYSICS AND CONTROLLED FUSION, Vol: 56, ISSN: 0741-3335

Journal article

Pozimski JK, Aslaninejad M, Dover N, Najmudin Z, Nichols RM, Posocco PAet al., 2013, A Ready-to-use Application of Laser-Plasma Accelerators using Gabor Lenses

Conference paper

Hughes C, Dover N, Najmudin Z, Posocco PAet al., 2013, Characterisation of Nitrogen Clusters and Gas Jet Targets Under Varied Nozzle Geometries

Conference paper

Robinson APL, Trines RMGM, Dover NP, Najmudin Zet al., 2012, Hole-boring radiation pressure acceleration as a basis for producing high-energy proton bunches, PLASMA PHYSICS AND CONTROLLED FUSION, Vol: 54, ISSN: 0741-3335

Journal article

Palmer CAJ, Schreiber J, Nagel SR, Dover NP, Bellei C, Beg FN, Bott S, Clarke RJ, Dangor AE, Hassan SM, Hilz P, Jung D, Kneip S, Mangles SPD, Lancaster KL, Rehman A, Robinson APL, Spindloe C, Szerypo J, Tatarakis M, Yeung M, Zepf M, Najmudin Zet al., 2012, Rayleigh-Taylor instability of an ultrathin foil accelerated by the radiation pressure of an intense laser., Phys Rev Lett, Vol: 108

We report experimental evidence for a Rayleigh-Taylor-like instability driven by radiation pressure of an ultraintense (10(21) W/cm(2)) laser pulse. The instability is witnessed by the highly modulated profile of the accelerated proton beam produced when the laser irradiates a 5 nm diamondlike carbon (90% C, 10% H) target. Clear anticorrelation between bubblelike modulations of the proton beam and transmitted laser profile further demonstrate the role of the radiation pressure in modulating the foil. Measurements of the modulation wavelength, and of the acceleration from Doppler-broadening of back-reflected light, agree quantitatively with particle-in-cell simulations performed for our experimental parameters and which confirm the existence of this instability.

Journal article

Dover NP, Najmudin Z, 2012, Ion acceleration in the radiation pressure regime with ultrashort pulse lasers, HIGH ENERGY DENSITY PHYSICS, Vol: 8, Pages: 170-174, ISSN: 1574-1818

Journal article

Palmer CAJ, Schreiber J, Nagel SR, Dover NP, Bellei C, Beg FN, Bott S, Clarke RJ, Dangor AE, Hassan SM, Hilz P, Jung D, Kneip S, Mangles SPD, Lancaster KL, Rehman A, Robinson APL, Spindloe C, Szerypo J, Tatarakis M, Yeung M, Zepf M, Najmudin Zet al., 2012, Rayleigh-Taylor Instability of an Ultrathin Foil Accelerated by the Radiation Pressure of an Intense Laser, PHYSICAL REVIEW LETTERS, Vol: 108, ISSN: 0031-9007

Journal article

Prasad R, Ter-Avetisyan S, Doria D, Quinn KE, Romagnani L, Zepf M, Borghesi M, Andreev A, Foster PS, Brenner CM, Gallegos P, Neely D, Green JS, Streeter MJV, Carroll DC, Tresca O, McKenna P, Dover NP, Palmer CAJ, Schreiber J, Najmudin Zet al., 2012, Acceleration of ions up to 20MeV/nucleon in the ultrashort, high-intensity regime, 179th International School of Physics Enrico Fermi on Laser-Plasma Acceleration, Publisher: IOS PRESS, Pages: 213-220, ISSN: 0074-784X

Conference paper

Pogorelsky IV, Dover NP, Babzien M, Bell AR, Dangor AE, Horbury T, Palmer CAJ, Polyanskiy M, Schreiber J, Schwartz S, Shkolnikov P, Yakimenko V, Najmudin Zet al., 2012, Ion Acceleration by Laser Hole-Boring into Plasmas, 15th Workshop on Advanced Accelerator Concepts (AAC), Publisher: AMER INST PHYSICS, Pages: 814-819, ISSN: 0094-243X

Conference paper

Prasad R, Ter-Avetisyan S, Doria D, Quinn KE, Romagnani L, Foster PS, Brenner CM, Green JS, Robinson APL, Gallegos P, Streeter MJV, Carroll DC, Tresca O, Dover N, Palmer CAJ, Schreiber J, Neely D, Najmudin Z, McKenna P, Zepf M, Borghesi Met al., 2011, Laser driven ion acceleration from ultra thin foils in the ultra relativistic intensity regime, Pages: 141-144

Conference paper

Prasad R, Ter-Avetisyan S, Doria D, Quinn KE, Romagnani L, Foster PS, Brenner CM, Green JS, Gallegos P, Streeter MJV, Carroll DC, Tresca O, Dover NP, Palmer CAJ, Schreiber J, Neely D, Najmudind Z, McKenna P, Zepf M, Borghesi Met al., 2011, Proton acceleration using 50 fs, high intensity ASTRA-Gemini laser pulses, NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT, Vol: 653, Pages: 113-115, ISSN: 0168-9002

Journal article

Prasad R, Andreev AA, Ter-Avetisyan S, Doria D, Quinn KE, Romagnani L, Brenner CM, Carroll DC, Dover NP, Neely D, Foster PS, Gallegos P, Green JS, McKenna P, Najmudin Z, Palmer CAJ, Schreiber J, Streeter MJV, Tresca O, Zepf M, Borghesi Met al., 2011, Fast ion acceleration from thin foils irradiated by ultra-high intensity, ultra-high contrast laser pulses, APPLIED PHYSICS LETTERS, Vol: 99, ISSN: 0003-6951

Journal article

Pogorelsky IV, Polyanskiy MN, Babzien M, Yakimenko V, Dover NP, Palmer CAJ, Najmudin Z, Schreiber J, Shkolnikov P, Dudnikova Get al., 2011, Laser-induced cavities and solitons in overcritical hydrogen plasma, LASER PHYSICS, Vol: 21, Pages: 1288-1294, ISSN: 1054-660X

Journal article

Najmudin Z, Palmer CAJ, Dover NP, Pogorelsky I, Babzien M, Dangor AE, Dudnikova GI, Foster PS, Green JS, Ispiriyan M, Neely D, Polyanskiy MN, Schreiber J, Shkolnikov P, Yakimenko Vet al., 2011, Observation of impurity free monoenergetic proton beams from the interaction of a CO2 laser with a gaseous target, 52nd Annual Meeting of the APS Division of Plasma Physics, Publisher: AMER INST PHYSICS, ISSN: 1070-664X

Conference paper

Streeter MJV, Foster PS, Cameron FH, Borghesi M, Brenner C, Carroll DC, Divall E, Dover NP, Dromey B, Gallegos P, Green JS, Hawkes S, Hooker CJ, Kar S, McKenna P, Nagel SR, Najmudin Z, Palmer CAJ, Prasad R, Quinn KE, Rajeev PP, Robinson APL, Romagnani L, Schreiber J, Spindloe C, Ter-Avetisyan S, Tresca O, Zepf M, Neely Det al., 2011, Relativistic plasma surfaces as an efficient second harmonic generator, NEW JOURNAL OF PHYSICS, Vol: 13, ISSN: 1367-2630

Journal article

Palmer CAJ, Dover NP, Pogorelsky I, Babzien M, Dudnikova GI, Ispiriyan M, Polyanskiy MN, Schreiber J, Shkolnikov P, Yakimenko V, Najmudin Zet al., 2011, Monoenergetic Proton Beams Accelerated by a Radiation Pressure Driven Shock, PHYSICAL REVIEW LETTERS, Vol: 106, ISSN: 0031-9007

Journal article

Pogorelsky I, Polyanskiy M, Yakimenko V, Ben-Zvi I, Shkolnikov P, Najmudin Z, Palmer CAJ, Dover NP, Oliva P, Carpinelli Met al., 2011, Proton- and x-ray beams generated by ultra-fast CO2 lasers for medical applications, Conference on Laser Acceleration of Electrons, Protons, and Ions and Medical Applications of Laser-Generated Secondary Sources of Radiation and Particles, Publisher: SPIE-INT SOC OPTICAL ENGINEERING, ISSN: 0277-786X

Conference paper

Borghesi M, Kar S, Prasad R, Kakolee FK, Quinn K, Ahmed H, Sarri G, Ramakrishna B, Qiao B, Geissler M, Ter-Avetisyan S, Zepf M, Schettino G, Stevens B, Tolley M, Ward A, Green J, Foster PF, Spindloe C, Gallegos P, Robinson AL, Neely D, Carroll DC, Tresca O, Yuan X, Quinn M, McKenna P, Dover N, Palmer C, Schreiber J, Najmudin Z, Sari I, Kraft M, Merchant M, Jeynes JC, Kirkby K, Fiorini F, Kirby D, Green Set al., 2011, Ion source development and radiobiology applications within the LIBRA project, Conference on Laser Acceleration of Electrons, Protons, and Ions and Medical Applications of Laser-Generated Secondary Sources of Radiation and Particles, Publisher: SPIE-INT SOC OPTICAL ENGINEERING, ISSN: 0277-786X

Conference paper

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