Publications


Proton-driven plasma wakefield acceleration: a path to the future of high-energy particle physics

PLASMA PHYSICS AND CONTROLLED FUSION 56 (2014) ARTN 084013

R Assmann, R Bingham, T Bohl, C Bracco, B Buttenschoen, A Butterworth, A Caldwell, S Chattopadhyay, S Cipiccia, E Feldbaumer, RA Fonseca, B Goddard, M Gross, O Grulke, E Gschwendtner, J Holloway, C Huang, D Jaroszynski, S Jolly, P Kempkes, N Lopes, K Lotov, J Machacek, SR Mandry, JW McKenzie, M Meddahi, BL Militsyn, N Moschuering, P Muggli, Z Najmudin, TCQ Noakes, PA Norreys, E Oez, A Pardons, A Petrenko, A Pukhov, K Rieger, O Reimann, H Ruhl, E Shaposhnikova, LO Silva, A Sosedkin, R Tarkeshian, RMGN Trines, T Tueckmantel, J Vieira, H Vincke, M Wing, G Xia


Observations of strong ion-ion correlations in dense plasmas

PHYSICS OF PLASMAS 21 (2014) ARTN 056302

T Ma, L Fletcher, A Pak, DA Chapman, RW Falcone, C Fortmann, E Galtier, DO Gericke, G Gregori, J Hastings, OL Landen, S Le Pape, HJ Lee, B Nagler, P Neumayer, D Turnbull, J Vorberger, TG White, K Wuensch, U Zastrau, SH Glenzer, T Doeppner


Comparison of BES measurements of ion-scale turbulence with direct gyro-kinetic simulations of MAST L-mode plasmas

Plasma Physics and Controlled Fusion 56 (2014)

AR Field, D Dunai, YC Ghim, P Hill, B McMillan, CM Roach, S Saarelma, AA Schekochihin, S Zoletnik

Observations of ion-scale (kyρi 1) density turbulence of relative amplitude 0.2% are available on the Mega Amp Spherical Tokamak (MAST) using a 2D (8 radial × 4 poloidal channel) imaging beam emission spectroscopy diagnostic. Spatial and temporal characteristics of this turbulence, i.e., amplitudes, correlation times, radial and perpendicular correlation lengths and apparent phase velocities of the density contours, are determined by means of correlation analysis. For a low-density, L-mode discharge with strong equilibrium flow shear exhibiting an internal transport barrier in the ion channel, the observed turbulence characteristics are compared with synthetic density turbulence data generated from global, non-linear, gyro-kinetic simulations using the particle-in-cell code NEMORB. This validation exercise highlights the need to include increasingly sophisticated physics, e.g., kinetic treatment of trapped electrons, equilibrium flow shear and collisions, to reproduce most of the characteristics of the observed turbulence. Even so, significant discrepancies remain: an underprediction by the simulations of the turbulence amplitude and heat flux at plasma periphery and the finding that the correlation times of the numerically simulated turbulence are typically two orders of magnitude longer than those measured in MAST. Comparison of these correlation times with various linear timescales suggests that, while the measured turbulence is strong and may be 'critically balanced', the simulated turbulence is weak. © 2014 IOP Publishing Ltd.


Firehose and Mirror Instabilities in a Collisionless Shearing Plasma

PHYSICAL REVIEW LETTERS 112 (2014) ARTN 205003

MW Kunz, AA Schekochihin, JM Stone


Evidence for a glassy state in strongly driven carbon.

Scientific reports 4 (2014) 5214-

CR Brown, DO Gericke, M Cammarata, BI Cho, T Döppner, K Engelhorn, E Förster, C Fortmann, D Fritz, E Galtier, SH Glenzer, M Harmand, P Heimann, NL Kugland, DQ Lamb, HJ Lee, RW Lee, H Lemke, M Makita, A Moinard, CD Murphy, B Nagler, P Neumayer, KU Plagemann, R Redmer, D Riley, FB Rosmej, P Sperling, S Toleikis, SM Vinko, J Vorberger, S White, TG White, K Wünsch, U Zastrau, D Zhu, T Tschentscher, G Gregori

Here, we report results of an experiment creating a transient, highly correlated carbon state using a combination of optical and x-ray lasers. Scattered x-rays reveal a highly ordered state with an electrostatic energy significantly exceeding the thermal energy of the ions. Strong Coulomb forces are predicted to induce nucleation into a crystalline ion structure within a few picoseconds. However, we observe no evidence of such phase transition after several tens of picoseconds but strong indications for an over-correlated fluid state. The experiment suggests a much slower nucleation and points to an intermediate glassy state where the ions are frozen close to their original positions in the fluid.


Local dependence of ion temperature gradient on magnetic configuration, rotational shear and turbulent heat flux in MAST

ArXiv (0)

Y-C Ghim, AR Field, AA Schekochihin, EG Highcock, C Michael, TMAST Team

Experimental data from the Mega Amp Spherical Tokamak (MAST) is used to show that the inverse gradient scale length of the ion temperature R/LTi (normalized to the major radius R) has its strongest local correlation with the rotational shear and the pitch angle of the magnetic field (or, equivalently, an inverse correlation with q/{\epsilon}, the safety factor/the inverse aspect ratio). Furthermore, R/LTi is found to be inversely correlated with the gyro-Bohm-normalized local turbulent heat flux estimated from the density fluctuation level measured using a 2D Beam Emission Spectroscopy (BES) diagnostic. These results can be explained in terms of the conjecture that the turbulent system adjusts to keep R/LTi close to a certain critical value (marginal for the excitation of turbulence) determined by local equilibrium parameters (although not necessarily by linear stability).


Electron-ion equilibration in ultrafast heated graphite.

Physical review letters 112 (2014) 145005-

TG White, NJ Hartley, B Borm, BJ Crowley, JW Harris, DC Hochhaus, T Kaempfer, K Li, P Neumayer, LK Pattison, F Pfeifer, S Richardson, AP Robinson, I Uschmann, G Gregori

We have employed fast electrons produced by intense laser illumination to isochorically heat thermal electrons in solid density carbon to temperatures of ∼10,000  K. Using time-resolved x-ray diffraction, the temperature evolution of the lattice ions is obtained through the Debye-Waller effect, and this directly relates to the electron-ion equilibration rate. This is shown to be considerably lower than predicted from ideal plasma models. We attribute this to strong ion coupling screening the electron-ion interaction.


SEARCHES FOR EXTENDED AND POINT-LIKE NEUTRINO SOURCES WITH FOUR YEARS OF ICECUBE DATA

ASTROPHYSICAL JOURNAL 796 (2014) ARTN 109

MG Aartsen, M Ackermann, J Adams, JA Aguilar, M Ahlers, M Ahrens, D Altmann, T Anderson, C Arguelles, TC Arlen, J Auffenberg, X Bai, SW Barwick, V Baum, JJ Beatty, JB Tjus, K-H Becker, S BenZvi, P Berghaus, D Berley, E Bernardini, A Bernhard, DZ Besson, G Binder, D Bindig, M Bissok, E Blaufuss, J Blumenthal, DJ Boersma, C Bohm, F Bos, D Bose, S Boeser, O Botner, L Brayeur, H-P Bretz, AM Brown, J Casey, M Casier, E Cheung, D Chirkin, A Christov, B Christy, K Clark, L Classen, F Clevermann, S Coenders, DF Cowen, AHC Silva, M Danninger, J Daughhetee, JC Davis, M Day, JPAM de Andre, C De Clercq, S De Ridder, P Desiati, KD de Vries, M de With, T DeYoung, JC Diaz-Velez, M Dunkman, R Eagan, B Eberhardt, B Eichmann, J Eisch, S Euler, PA Evenson, O Fadiran, AR Fazely, A Fedynitch, J Feintzeig, J Felde, T Feusels, K Filimonov, C Finley, T Fischer-Wasels, S Flis, A Franckowiak, K Frantzen, T Fuchs, TK Gaisser, J Gallagher, L Gerhardt, D Gier, L Gladstone, T Gluesenkamp, A Goldschmidt, G Golup, JG Gonzalez, JA Goodman, D Gora, DT Grandmont, D Grant, P Gretskov, JC Groh, A Gross, C Ha, C Haack, AH Ismail, P Hallen, A Hallgren, F Halzen, K Hanson, D Hebecker, D Heereman, D Heinen, K Helbing, R Hellauer, D Hellwig, S Hickford, GC Hill, KD Hoffman, R Hoffmann, A Homeier, K Hoshina, F Huang, W Huelsnitz, PO Hulth, K Hultqvist, S Hussain, A Ishihara, E Jacobi, J Jacobsen, K Jagielski, GS Japaridze, K Jero, O Jlelati, M Jurkovic, B Kaminsky, A Kappes, T Karg, A Karle, M Kauer, JL Kelley, A Kheirandish, J Kiryluk, J Klaes, SR Klein, J-H Koehne, G Kohnen, H Kolanoski, A Koob, L Koepke, C Kopper, S Kopper, DJ Koskinen, M Kowalski, A Kriesten, K Krings, G Kroll, M Kroll, J Kunnen, N Kurahashi, T Kuwabara, M Labare, DT Larsen, MJ Larson, M Lesiak-Bzdak, M Leuermann, J Leute, J Luenemann, O Macias, J Madsen, G Maggi, R Maruyama, K Mase, HS Matis, R Maunu, F McNally, K Meagher, M Medici, A Meli, T Meures, S Miarecki, E Middell, E Middlemas, N Milke, J Miller, L Mohrmann, T Montaruli, R Morse, R Nahnhauer, U Naumann, H Niederhausen, SC Nowicki, DR Nygren, A Obertacke, S Odrowski, A Olivas, A Omairat, A O'Murchadha, T Palczewski, L Paul, O Penek, JA Pepper, CPDL Heros, C Pfendner, D Pieloth, E Pinat, J Posselt, PB Price, GT Przybylski, J Puetz, M Quinnan, L Raedel, M Rameez, K Rawlins, P Redl, I Rees, R Reimann, E Resconi, W Rhode, M Richman, B Riedel, S Robertson, JP Rodrigues, M Rongen, C Rott, T Ruhe, B Ruzybayev, D Ryckbosch, SM Saba, H-G Sander, J Sandroos, M Santander, S Sarkar, K Schatto, F Scheriau, T Schmidt, M Schmitz, S Schoenen, S Schoeneberg, A Schoenwald, A Schukraft, L Schulte, O Schulz, D Seckel, Y Sestayo, S Seunarine, R Shanidze, C Sheremata, MWE Smith, D Soldin, GM Spiczak, C Spiering, M Stamatikos, T Stanev, NA Stanisha, A Stasik, T Stezelberger, RG Stokstad, A Stoessl, EA Strahler, R Strom, NL Strotjohann, GW Sullivan, H Taavola, I Taboada, A Tamburro, A Tepe, S Ter-Antonyan, A Terliuk, G Tesic, S Tilav, PA Toale, MN Tobin, D Tosi, M Tselengidou, E Unger, M Usner, S Vallecorsa, N van Eijndhoven, J Vandenbroucke, J van Santen, M Vehring, M Voge, M Vraeghe, C Walck, M Wallraff, C Weaver, M Wellons, C Wendt, S Westerhoff, BJ Whelan, N Whitehorn, C Wichary, K Wiebe, CH Wiebusch, DR Williams, H Wissing, M Wolf, TR Wood, K Woschnagg, DL Xu, XW Xu, JP Yanez, G Yodh, S Yoshida, P Zarzhitsky, J Ziemann, S Zierke, M Zoll, I Collaboration


Compact laser accelerators for X-ray phase-contrast imaging

Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 372 (2014)

Z Najmudin, S Kneip, MS Bloom, SPD Mangles, O Chekhlov, AE Dangor, A Dopp, K Ertel, SJ Hawkes, J Holloway, CJ Hooker, J Jiang, NC Lopes, H Nakamura, PA Norreys, PP Rajeev, C Russo, MJV Streeter, DR Symes, M Wing

Advances in X-ray imaging techniques have been driven by advances in novel X-ray sources. The latest fourth-generation X-ray sources can boast large photon fluxes at unprecedented brightness. However, the large size of these facilities means that these sources are not available for everyday applications. With advances in laser plasma acceleration, electron beams can now be generated at energies comparable to those used in light sources, but in university-sized laboratories. By making use of the strong transverse focusing of plasma accelerators, bright sources of betatron radiation have been produced. Here, we demonstrate phase-contrast imaging of a biological sample for the first time by radiation generated by GeV electron beams produced by a laser accelerator. The work was performed using a greater than 300TW laser, which allowed the energy of the synchrotron source to be extended to the 10100 keV range. © 2014 The Author(s) Published by the Royal Society. All rights reserved.


Erratum: "Correlations at large scales and the onset of turbulence in the fast solar wind" (2013, ApJ, 778, 177)

Astrophysical Journal 782 (2014)

RT Wicks, DA Roberts, A Mallet, AA Schekochihin, TS Horbury, CHK Chen


Optimizing stellarators for large flows

PLASMA PHYSICS AND CONTROLLED FUSION 56 (2014) ARTN 094003

I Calvo, FI Parra, J Arturo Alonso, J Luis Velasco


Interstellar medium. Pseudo-three-dimensional maps of the diffuse interstellar band at 862 nm.

Science (New York, N.Y.) 345 (2014) 791-795

J Kos, T Zwitter, R Wyse, O Bienaymé, J Binney, J Bland-Hawthorn, K Freeman, BK Gibson, G Gilmore, EK Grebel, A Helmi, G Kordopatis, U Munari, J Navarro, Q Parker, WA Reid, G Seabroke, S Sharma, A Siebert, A Siviero, M Steinmetz, FG Watson, ME Williams

The diffuse interstellar bands (DIBs) are absorption lines observed in visual and near-infrared spectra of stars. Understanding their origin in the interstellar medium is one of the oldest problems in astronomical spectroscopy, as DIBs have been known since 1922. In a completely new approach to understanding DIBs, we combined information from nearly 500,000 stellar spectra obtained by the massive spectroscopic survey RAVE (Radial Velocity Experiment) to produce the first pseudo-three-dimensional map of the strength of the DIB at 8620 angstroms covering the nearest 3 kiloparsecs from the Sun, and show that it follows our independently constructed spatial distribution of extinction by interstellar dust along the Galactic plane. Despite having a similar distribution in the Galactic plane, the DIB 8620 carrier has a significantly larger vertical scale height than the dust. Even if one DIB may not represent the general DIB population, our observations outline the future direction of DIB research.


Focus on high energy density physics

New Journal of Physics 16 (2014)

R Paul Drake, P Norreys

High-energy-density physics concerns the behavior of systems at high pressure, often involving the interplay of plasma, relativistic, quantum mechanical and electromagnetic effects. The field is growing rapidly in its scope of activity thanks to advances in experimental, laser and computational technologies. This 'focus on' collection presents papers discussing forefront research that spans the field, providing a sense of its breadth and of the interlinking of its parts. © 2014 IOP Publishing Ltd and Deutsche Physikalische Gesellschaft.


The Gaia-ESO Survey: The analysis of high-resolution UVES spectra of FGK-type stars

ASTRONOMY & ASTROPHYSICS 570 (2014) ARTN A122

R Smiljanic, AJ Korn, M Bergemann, A Frasca, L Magrini, T Masseron, E Pancino, G Ruchti, I San Roman, L Sbordone, SG Sousa, H Tabernero, G Tautvaisiene, M Valentini, M Weber, CC Worley, VZ Adibekyan, C Allende Prieto, G Barisevicius, K Biazzo, S Blanco-Cuaresma, P Bonifacio, A Bragaglia, E Caffau, T Cantat-Gaudin, Y Chorniy, P de Laverny, E Delgado-Mena, P Donati, S Duffau, E Franciosini, E Friel, D Geisler, JI Gonzalez Hernandez, P Gruyters, G Guiglion, CJ Hansen, U Heiter, V Hill, HR Jacobson, P Jofre, H Jonsson, AC Lanzafame, C Lardo, H-G Ludwig, E Maiorca, S Mikolaitis, D Montes, T Morel, A Mucciarelli, C Munoz, T Nordlander, L Pasquini, E Puzeras, A Recio-Blanco, N Ryde, G Sacco, NC Santos, AM Serenelli, R Sordo, C Soubiran, L Spina, M Steffen, A Vallenari, S Van Eck, S Villanova, G Gilmore, S Randich, M Asplund, J Binney, J Drew, S Feltzing, A Ferguson, R Jeffries, G Micela, I Negueruela, T Prusti, H-W Rix, E Alfaro, C Babusiaux, T Bensby, R Blomme, E Flaccomio, P Francois, M Irwin, S Koposov, N Walton, A Bayo, G Carraro, MT Costado, F Damiani, B Edvardsson, A Hourihane, R Jackson, J Lewis, K Lind, G Marconi, C Martayan, L Monaco, L Morbidelli, L Prisinzano, S Zaggia


Non-thermal enhancement of electron–positron pair creation in burning thermonuclear laboratory plasmas

High Energy Density Physics 13 (2014) C

EG Hill, SJ Rose


A hadronic explanation of the lepton anomaly

COSMIC RAY ANISOTROPY WORKSHOP 2013 (CRA2013) 531 (2014) UNSP 012008

P Mertsch, S Sarkar, IOP


In-depth Plasma-Wave Heating of Dense Plasma Irradiated by Short Laser Pulses

Physical Review Letters 113 (2014)

M Sherlock, EG Hill, RG Evans, SJ Rose, W Rozmus


IceCube-Gen2: A Vision for the Future of Neutrino Astronomy in Antarctica

(2014)

MG Aartsen, others


Suppression of local heat flux in a turbulent magnetized intracluster medium

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 440 (2014) 1153-1164

SV Komarov, EM Churazov, AA Schekochihin, JA ZuHone


KINEMATIC MODELING OF THE MILKY WAY USING THE RAVE AND GCS STELLAR SURVEYS

ASTROPHYSICAL JOURNAL 793 (2014) ARTN 51

S Sharma, J Bland-Hawthorn, J Binney, KC Freeman, M Steinmetz, C Boeche, O Bienayme, BK Gibson, GF Gilmore, EK Grebel, A Helmi, G Kordopatis, U Munari, JF Navarro, QA Parker, WA Reid, GM Seabroke, A Siebert, F Watson, MEK Williams, RFG Wyse, T Zwitter