Publications


Large tangential electric fields in plasmas close to temperature screening

Plasma Physics and Controlled Fusion 60 (2018)

JL Velasco, I Calvo, JM García-Regana, FI Parra, S Satake, JA Alonso

© 2018 Laboratorio Nacional de Fusion, CIEMAT. Low collisionality stellarator plasmas usually display a large negative radial electric field that has been expected to cause accumulation of impurities due to their high charge number. In this paper, two combined effects that can potentially modify this scenario are discussed. First, it is shown that, in low collisionality plasmas, the kinetic contribution of the electrons to the radial electric field can make it negative but small, bringing the plasma close to impurity temperature screening (i.e., to a situation in which the ion temperature gradient is the main drive of impurity transport and causes outward flux); in plasmas of very low collisionality, such as those of the large helical device displaying impurity hole (Ida et al (The LHD Experimental Group) 2009 Phys. Plasmas 16 056111; Yoshinuma et al (The LHD Experimental Group) 2009 Nucl. Fusion 49 062002), screening may actually occur. Second, the component of the electric field that is tangent to the flux surface (in other words, the variation of the electrostatic potential on the flux surface), although smaller than the radial component, has recently been suggested to be an additional relevant drive for radial impurity transport. Here, it is explained that, especially when the radial electric field is small, the tangential magnetic drift has to be kept in order to correctly compute the tangential electric field, that can be larger than previously expected. This can have a strong impact on impurity transport, as we illustrate by means of simulations using the newly developed code kinetic orbit-averaging-solver for stellarators, although it is not enough to explain by itself the behavior of the fluxes in situations like the impurity hole.


Axion particle production in a laser-induced dynamical spacetime

Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics 777 (2018) 388-393

MA Wadud, B King, R Bingham, G Gregori

© 2017 The Authors We consider the dynamics of a charged particle (e.g., an electron) oscillating in a laser field in flat spacetime and describe it in terms of the variable mass metric. By applying Einstein's equivalence principle, we show that, after representing the electron motion in a time-dependent manner, the variable mass metric takes the form of the Friedmann–Lemaître–Robertson–Walker metric. We quantize a pseudo-scalar field in this spacetime and derive the production rate of electrically neutral, spinless particles. We show that this approach can provide an alternative experimental method to axion searches.


Search for nonstandard neutrino interactions with IceCube DeepCore

Physical Review D, Particles and fields American Physical Society 97 (2018) ARTN 072009

MG Aartsen, M Ackermann, J Adams, JA Aguilar, M Ahlers, M Ahrens, I Al Samarai, D Altmann, K Andeen, T Anderson, I Ansseau, G Anton, C Arguelles, J Auffenberg, S Axani, H Bagherpour, X Bai, JP Barron, SW Barwick, V Baum, R Bay, JJ Beatty, JB Tjus, K-H Becker, S BenZvi, D Berley, E Bernardini, DZ Besson, G Binder, D Bindig, E Blaufuss, S Blot, C Bohm, M Boerner, F Bos, D Bose, S Boeser, O Botner, E Bourbeau, J Bourbeau, F Bradascio, J Braun, L Brayeur, M Brenzke, H-P Bretz, S Bron, J Brostean-Kaiser, A Burgman, T Carver, J Casey, M Casier, E Cheung, D Chirkin, A Christov, K Clark, L Classen, S Coenders, GH Collin, JM Conrad, DF Cowen, R Cross, M Day, JPAM de Andre, C De Clercq, JJ DeLaunay, H Dembinski, S De Ridder, P Desiati, KD de Vries, G de Wasseige, M de With, T DeYoung, JC Diaz-Velez, V di Lorenzo, H Dujmovic, JP Dumm, M Dunkman, E Dvorak, B Eberhardt, T Ehrhardt, B Eichmann, P Eller, PA Evenson, S Fahey, AR Fazely, J Felde, K Filimonov, C Finley, S Flis, A Franckowiak, E Friedman, T Fuchs, TK Gaisser, J Gallagher, L Gerhardt, K Ghorbani, W Giang, T Glauch, T Gluesenkamp, A Goldschmidt, JG Gonzalez, D Grant, Z Griffith, C Haack, A Hallgren, F Halzen, K Hanson, D Hebecker, D Heereman, K Helbing, R Hellauer, S Hickford, J Hignight, GC Hill, KD Hoffman, R Hoffmann, B Hokanson-Fasig, K Hoshina, F Huang, M Huber, K Hultqvist, M Huennefeld, S In, A Ishihara, E Jacobi, GS Japaridze, M Jeong, K Jero, BJP Jones, P Kalaczynski, W Kang, A Kappes, T Karg, A Karle, U Katz, M Kauer, A Keivani, JL Kelley, A Kheirandish, J Kim, M Kim, T Kintscher, C Kirby, J Kiryluk, T Kittler, SR Klein, G Kohnen, R Koirala, H Kolanoski, L Koepke, C Kopper, S Kopper, JP Koschinsky, DJ Koskinen, M Kowalski, K Krings, M Kroll, G Kruckl, J Kunnen, S Kunwar, N Kurahashi, T Kuwabara, A Kyriacou, M Labare, JL Lanfranchi, MJ Larson, F Lauber, D Lennarz, M Lesiak-Bzdak, M Leuermann, QR Liu, L Lu, J Luenemann, W Luszczak, J Madsen, G Maggi, KBM Mahn, S Mancina, R Maruyama, K Mase, R Maunu, F McNally, K Meagher, M Medici, M Meier, T Menne, G Merino, T Meures, S Miarecki, J Micallef, G Momente, T Montaruli, RW Moore, M Moulai, R Nahnhauer, P Nakarmi, U Naumann, G Neer, H Niederhausen, SC Nowicki, DR Nygren, AO Pollmann, A Olivas, A O'Murchadha, T Palczewski, H Pandya, DV Pankova, P Peiffer, JA Pepper, CP de los Heros, D Pieloth, E Pinat, M Plum, PB Price, GT Przybylski, C Raab, L Raedel, M Rameez, K Rawlins, IC Rea, R Reimann, B Relethford, M Relich, E Resconi, W Rhode, M Richman, S Robertson, M Rongen, C Rott, T Ruhe, D Ryckbosch, D Rysewyk, T Saelzer, SES Herrera, A Sandrock, J Sandroos, M Santander, S Sarkar, S Sarkar, K Satalecka, P Schlunder, T Schmidt, A Schneider, S Schoenen, S Schoeneberg, L Schumacher, D Seckel, S Seunarine, J Soedingrekso, D Soldin, M Song, GM Spiczak, C Spiering, J Stachurska, M Stamatikos, T Stanev, A Stasik, J Stettner, A Steuer, T Stezelberger, RG Stokstad, A Stossl, NL Strotjohann, T Stuttard, GW Sullivan, M Sutherland, I Taboada, J Tatar, F Tenholt, S Ter-Antonyan, A Terliuk, G Tesic, S Tilav, PA Toale, MN Tobin, S Toscano, D Tosi, M Tselengidou, CF Tung, A Turcati, CF Turley, B Ty, E Unger, M Usner, J Vandenbroucke, W Van Driessche, N van Eijndhoven, S Vanheule, J van Santen, M Vehring, E Vogel, M Vraeghe, C Walck, A Wallace, M Wallraff, FD Wandler, N Wandkowsky, A Waza, C Weaver, MJ Weiss, C Wendt, J Werthebach, S Westerhoff, BJ Whelan, K Wiebe, CH Wiebusch, L Wille, DR Williams, L Wills, M Wolf, J Wood, TR Wood, E Woolsey, K Woschnagg, DL Xu, XW Xu, Y Xu, JP Yanez, G Yodh, S Yoshida, T Yuan, M Zoll, I Collaboration


A Search for Neutrino Emission from Fast Radio Bursts with Six Years of IceCube Data

Astrophysical Journal University of Chicago Press 857 (2018) ARTN 117

MG Aartsen, M Ackermann, J Adams, JA Aguilar, M Ahlers, M Ahrens, I Al Samarai, D Altmann, K Andeen, T Anderson, I Ansseau, G Anton, C Arguelles, J Auffenberg, S Axani, H Bagherpour, X Bai, JP Barron, SW Barwick, V Baum, R Bay, JJ Beatty, JB Tjus, K-H Becker, S BenZvi, D Berley, E Bernardini, DZ Besson, G Binder, D Bindig, E Blaufuss, S Blot, C Bohm, M Boerner, F Bos, S Boeser, O Botner, E Bourbeau, J Bourbeau, F Bradascio, J Braun, M Brenzke, H-P Bretz, S Bron, J Brostean-Kaiser, A Burgman, RS Busse, T Carver, E Cheung, D Chirkin, A Christov, K Clark, L Classen, GH Collins, JM Conrad, P Coppin, P Correa, DF Cowen, R Cross, P Dave, M Day, JPAM de Andre, C De Clercq, JJ DeLaunay, H Dembinski, S De Ridder, P Desiati, KD de Vries, G de Wasseige, M de With, T DeYoung, JC Diaz-Velez, V di Lorenzo, H Dujmovic, JP Dumm, M Dunkman, E Dvorak, B Eberhardt, T Ehrhardt, B Eichmann, P Eller, PA Evenson, S Fahey, AR Fazely, J Felde, K Filimonov, C Finley, S Flis, A Franckowiak, E Friedman, A Fritz, TK Gaisser, J Gallagher, L Gerhardt, K Ghorbani, W Giang, T Glauch, T Gluesenkamp, A Goldschmidt, JG Gonzalez, D Grant, Z Griffith, C Haack, A Hallgren, F Halzen, K Hanson, D Hebecker, D Heereman, K Helbing, R Hellauer, S Hickford, J Hignight, GC Hill, KD Hoffman, R Hoffmann, T Hoinka, B Hokanson-Fasig, K Hoshina, F Huang, M Huber, K Hultqvist, M Huennefele, R Hussain, S In, N Iovine, A Ishihara, E Jacobi, GS Japaridze, M Jeong, K Jero, BJP Jones, P Kalaczynski, W Kang, A Kappes, D Kappesser, T Karg, A Karle, U Katz, M Kauer, A Keivani, JL Kelley, A Kheirandish, J Kim, M Kim, T Kintscher, J Kiryluk, T Kittler, SR Klein, R Koirala, H Kolanoski, L Koepke, C Kopper, S Kopper, JP Koschinsky, DJ Koskinen, M Kowalski, K Krings, M Kroll, G Krueckl, S Kunwar, N Kurahashi, T Kuwabara, A Kyriacou, M Labare, JL Lanfranchi, MJ Larson, F Lauber, K Leonard, M Lesiak-Bzdak, M Leuermann, QR Liu, CJL Mariscal, L Lu, J Luenemann, W Luszczak, J Madsen, G Maggi, KBM Mahn, S Mancina, R Maruyama, K Mase, R Maunu, K Meagher, M Medici, M Meier, T Menne, G Merino, T Meures, S Miarecki, J Micallef, G Momente, T Montaruli, RW Moore, M Moulai, R Nahnhauer, P Nakarmi, U Naumann, G Neer, H Niederhausen, SC Nowicki, DR Nygren, AO Pollmann, A Olivas, A O'Murchadha, E O'Sullivan, T Palczewski, H Pandya, DV Pankova, P Peiffer, JA Pepper, CP de los Heros, D Pieloth, E Pinat, M Plum, PB Price, GT Przybylski, C Raab, L Raedel, M Rameez, L Rauch, K Rawlins, IC Rea, R Reimann, B Relethford, M Relich, E Resconi, W Rhode, M Richman, S Robertson, M Rongen, C Rott, T Ruhe, D Ryckbosch, D Rysewyk, I Safa, T Saelzer, SES Herrera, A Sandrock, J Sandroos, M Santander, S Sarkar, K Satalecka, P Schlunder, T Schmidt, A Schneider, S Schoenen, S Schoenberg, L Schumacher, S Sclafani, D Seckel, S Seunarine, J Soedingrekso, D Soldin, M Song, GM Spiczak, C Spiering, J Stachurska, M Stamatikos, T Stanev, A Stasik, R Stein, J Stettner, A Steuer, T Stezelberger, RG Stokstad, A Stossl, NL Strotjohann, T Stuttard, GW Sullivan, M Sutherland, I Taboada, J Tatar, F Tenholt, S Ter-Antonyan, A Terliuk, S Tilav, PA Toale, MN Tobin, C Toennis, S Toscano, D Tosi, M Tselengidou, CF Tung, A Turcati, CF Turley, B Ty, E Unger, M Usner, J Vandenbroucke, W Van Driessche, D van Eijk, N van Eijndhoven, S Vanheule, J van Santen, E Vogel, M Vraeghe, C Walck, A Wallace, M Wallraff, FD Wandler, N Wandkowsky, A Waza, C Weaver, MJ Weiss, C Wendt, J Werthebach, S Westerhoff, BJ Whelan, K Wiebe, CH Wiebusch, L Wille, DR Williams, L Wills, M Wolf, J Wood, TR Wood, E Woolsey, K Woschnagg, DL Xu, XW Xu, Y Xu, JP Yanez, G Yodh, S Yoshida, T Yuan, I Collaboration


Gas flows in the circumgalactic medium around simulated high-redshift galaxies

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 473 (2018) 4279-4301

PD Mitchell, J Blaizot, J Devriendt, T Kimm, L Michel-Dansac, J Rosdahl, A Slyz


Electron acceleration by wave turbulence in a magnetized plasma

Nature Physics 14 (2018) 475-479

A Rigby, F Cruz, B Albertazzi, R Bamford, AR Bell, JE Cross, F Fraschetti, P Graham, Y Hara, PM Kozlowski, Y Kuramitsu, DQ Lamb, S Lebedev, JR Marques, F Miniati, T Morita, M Oliver, B Reville, Y Sakawa, S Sarkar, C Spindloe, R Trines, P Tzeferacos, LO Silva, R Bingham, M Koenig, G Gregori

© 2018 The Author(s). Astrophysical shocks are commonly revealed by the non-thermal emission of energetic electrons accelerated in situ1-3. Strong shocks are expected to accelerate particles to very high energies4-6; however, they require a source of particles with velocities fast enough to permit multiple shock crossings. While the resulting diffusive shock acceleration4process can account for observations, the kinetic physics regulating the continuous injection of non-thermal particles is not well understood. Indeed, this injection problem is particularly acute for electrons, which rely on high-frequency plasma fluctuations to raise them above the thermal pool7,8. Here we show, using laboratory laser-produced shock experiments, that, in the presence of a strong magnetic field, significant electron pre-heating is achieved. We demonstrate that the key mechanism in producing these energetic electrons is through the generation of lower-hybrid turbulence via shock-reflected ions. Our experimental results are analogous to many astrophysical systems, including the interaction of a comet with the solar wind9, a setting where electron acceleration via lower-hybrid waves is possible.


Measurement of Atmospheric Neutrino Oscillations at 6-56 GeV with IceCube DeepCore.

Physical Review Letters 120 (2018) 071801-071801

MG Aartsen, M Ackermann, J Adams, JA Aguilar, M Ahlers, M Ahrens, I Al Samarai, D Altmann, K Andeen, T Anderson, I Ansseau, G Anton, C Argüelles, J Auffenberg, S Axani, H Bagherpour, X Bai, JP Barron, SW Barwick, V Baum, R Bay, JJ Beatty, J Becker Tjus, K-H Becker, S BenZvi, D Berley, E Bernardini, DZ Besson, G Binder, D Bindig, E Blaufuss, S Blot, C Bohm, M Börner, F Bos, D Bose, S Böser, O Botner, J Bourbeau, F Bradascio, J Braun, L Brayeur, M Brenzke, H-P Bretz, S Bron, J Brostean-Kaiser, A Burgman, T Carver, J Casey, M Casier, E Cheung, D Chirkin, A Christov, K Clark, L Classen, S Coenders, GH Collin, JM Conrad, DF Cowen, R Cross, M Day, JPAM de André, C De Clercq, JJ DeLaunay, H Dembinski, S De Ridder, P Desiati, KD de Vries, G de Wasseige, M de With, T DeYoung, JC Díaz-Vélez, V di Lorenzo, H Dujmovic, JP Dumm, M Dunkman, B Eberhardt, T Ehrhardt, B Eichmann, P Eller, PA Evenson, S Fahey, AR Fazely, J Felde, K Filimonov, C Finley, S Flis, A Franckowiak, E Friedman, T Fuchs, TK Gaisser, J Gallagher, L Gerhardt, K Ghorbani, W Giang, T Glauch, T Glüsenkamp, A Goldschmidt, JG Gonzalez, D Grant, Z Griffith, C Haack, A Hallgren, F Halzen, K Hanson, D Hebecker, D Heereman, K Helbing, R Hellauer, S Hickford, J Hignight, GC Hill, KD Hoffman, R Hoffmann, B Hokanson-Fasig, K Hoshina, F Huang, M Huber, K Hultqvist, M Hünnefeld, S In, A Ishihara, E Jacobi, GS Japaridze, M Jeong, K Jero, BJP Jones, P Kalaczynski, W Kang, A Kappes, T Karg, A Karle, U Katz, M Kauer, A Keivani, JL Kelley, A Kheirandish, J Kim, M Kim, T Kintscher, J Kiryluk, T Kittler, SR Klein, G Kohnen, R Koirala, H Kolanoski, L Köpke, C Kopper, S Kopper, JP Koschinsky, DJ Koskinen, M Kowalski, K Krings, M Kroll, G Krückl, J Kunnen, S Kunwar, N Kurahashi, T Kuwabara, A Kyriacou, M Labare, JL Lanfranchi, MJ Larson, F Lauber, D Lennarz, M Lesiak-Bzdak, M Leuermann, QR Liu, L Lu, J Lünemann, W Luszczak, J Madsen, G Maggi, KBM Mahn, S Mancina, R Maruyama, K Mase, R Maunu, F McNally, K Meagher, M Medici, M Meier, T Menne, G Merino, T Meures, S Miarecki, J Micallef, G Momenté, T Montaruli, RW Moore, M Moulai, R Nahnhauer, P Nakarmi, U Naumann, G Neer, H Niederhausen, SC Nowicki, DR Nygren, A Obertacke Pollmann, A Olivas, A O'Murchadha, T Palczewski, H Pandya, DV Pankova, P Peiffer, JA Pepper, C Pérez de Los Heros, D Pieloth, E Pinat, M Plum, PB Price, GT Przybylski, C Raab, L Rädel, M Rameez, K Rawlins, IC Rea, R Reimann, B Relethford, M Relich, E Resconi, W Rhode, M Richman, S Robertson, M Rongen, C Rott, T Ruhe, D Ryckbosch, D Rysewyk, T Sälzer, SE Sanchez Herrera, A Sandrock, J Sandroos, S Sarkar, S Sarkar, K Satalecka, P Schlunder, T Schmidt, A Schneider, S Schoenen, S Schöneberg, L Schumacher, D Seckel, S Seunarine, J Soedingrekso, D Soldin, M Song, GM Spiczak, C Spiering, J Stachurska, M Stamatikos, T Stanev, A Stasik, J Stettner, A Steuer, T Stezelberger, RG Stokstad, A Stößl, NL Strotjohann, GW Sullivan, M Sutherland, I Taboada, J Tatar, F Tenholt, S Ter-Antonyan, A Terliuk, G Tešić, S Tilav, PA Toale, MN Tobin, S Toscano, D Tosi, M Tselengidou, CF Tung, A Turcati, CF Turley, B Ty, E Unger, M Usner, J Vandenbroucke, W Van Driessche, N van Eijndhoven, S Vanheule, J van Santen, M Vehring, E Vogel, M Vraeghe, C Walck, A Wallace, M Wallraff, FD Wandler, N Wandkowsky, A Waza, C Weaver, MJ Weiss, C Wendt, J Werthebach, S Westerhoff, BJ Whelan, K Wiebe, CH Wiebusch, L Wille, DR Williams, L Wills, M Wolf, J Wood, TR Wood, E Woolsey, K Woschnagg, DL Xu, XW Xu, Y Xu, JP Yanez, G Yodh, S Yoshida, T Yuan, M Zoll

We present a measurement of the atmospheric neutrino oscillation parameters using three years of data from the IceCube Neutrino Observatory. The DeepCore infill array in the center of IceCube enables the detection and reconstruction of neutrinos produced by the interaction of cosmic rays in Earth's atmosphere at energies as low as ∼5  GeV. That energy threshold permits measurements of muon neutrino disappearance, over a range of baselines up to the diameter of the Earth, probing the same range of L/E_{ν} as long-baseline experiments but with substantially higher-energy neutrinos. This analysis uses neutrinos from the full sky with reconstructed energies from 5.6 to 56 GeV. We measure Δm_{32}^{2}=2.31_{-0.13}^{+0.11}×10^{-3}  eV^{2} and sin^{2}θ_{23}=0.51_{-0.09}^{+0.07}, assuming normal neutrino mass ordering. These results are consistent with, and of similar precision to, those from accelerator- and reactor-based experiments.


Polarization of Sunyaev-Zel'dovich signal due to electron pressure anisotropy in galaxy clusters

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 474 (2018) 2389-2400

I Khabibullin, S Komarov, E Churazov, A Schekochihin


Analytical modelling of the expansion of a solid obstacle interacting with a radiative shock

HIGH POWER LASER SCIENCE AND ENGINEERING 6 (2018) ARTN e30

T Michel, E Falize, B Albertazzi, G Rigon, Y Sakawa, T Sano, H Shimogawara, R Kumar, T Morita, C Michaut, A Casner, P Barroso, P Mabey, Y Kuramitsu, S Laffite, LVB Som, G Gregori, R Kodama, N Ozaki, P Tzeferacos, D Lamb, M Koenig


The TRAPPIST-1 system: orbital evolution, tidal dissipation, formation and habitability

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 476 (2018) 5032-5056

JCB Papaloizou, E Szuszkiewicz, C Terquem


An excess of massive stars in the local 30 Doradus starburst.

Science (New York, N.Y.) 359 (2018) 69-71

FRN Schneider, H Sana, CJ Evans, JM Bestenlehner, N Castro, L Fossati, G Gräfener, N Langer, OH Ramírez-Agudelo, C Sabín-Sanjulián, S Simón-Díaz, F Tramper, PA Crowther, A de Koter, SE de Mink, PL Dufton, M Garcia, M Gieles, V Hénault-Brunet, A Herrero, RG Izzard, V Kalari, DJ Lennon, J Maíz Apellániz, N Markova, F Najarro, P Podsiadlowski, J Puls, WD Taylor, JT van Loon, JS Vink, C Norman

The 30 Doradus star-forming region in the Large Magellanic Cloud is a nearby analog of large star-formation events in the distant universe. We determined the recent formation history and the initial mass function (IMF) of massive stars in 30 Doradus on the basis of spectroscopic observations of 247 stars more massive than 15 solar masses ([Formula: see text]). The main episode of massive star formation began about 8 million years (My) ago, and the star-formation rate seems to have declined in the last 1 My. The IMF is densely sampled up to 200 [Formula: see text] and contains 32 ± 12% more stars above 30 [Formula: see text] than predicted by a standard Salpeter IMF. In the mass range of 15 to 200 [Formula: see text], the IMF power-law exponent is [Formula: see text], shallower than the Salpeter value of 2.35.


Experimental platform for the investigation of magnetized-reverse-shock dynamics in the context of POLAR

HIGH POWER LASER SCIENCE AND ENGINEERING 6 (2018) ARTN e43

B Albertazzi, E Falize, A Pelka, F Brack, F Kroll, R Yurchak, E Brambrink, P Mabey, N Ozaki, S Pikuz, LVB Som, JM Bonnet-Bidaud, JE Cross, E Filippov, G Gregori, R Kodama, M Mouchet, T Morita, Y Sakawa, RP Drake, CC Kuranz, MJ-E Manuel, C Li, P Tzeferacos, D Lamb, U Schramm, M Koenig


Channel optimization of high-intensity laser beams in millimeter-scale plasmas.

Physical review. E 97 (2018) 043208-

L Ceurvorst, A Savin, N Ratan, MF Kasim, J Sadler, PA Norreys, H Habara, KA Tanaka, S Zhang, MS Wei, S Ivancic, DH Froula, W Theobald

Channeling experiments were performed at the OMEGA EP facility using relativistic intensity (>10^{18}W/cm^{2}) kilojoule laser pulses through large density scale length (∼390-570 μm) laser-produced plasmas, demonstrating the effects of the pulse's focal location and intensity as well as the plasma's temperature on the resulting channel formation. The results show deeper channeling when focused into hot plasmas and at lower densities, as expected. However, contrary to previous large-scale particle-in-cell studies, the results also indicate deeper penetration by short (10 ps), intense pulses compared to their longer-duration equivalents. This new observation has many implications for future laser-plasma research in the relativistic regime.


Do SN 2002cx-like and SN Ia-CSM Objects Share the Same Origin?

ASTROPHYSICAL JOURNAL 861 (2018) ARTN 127

X Meng, P Podsiadlowski


Advantages to a diverging Raman amplifier

Communications Physics 1 (2018)

JD Sadler, LO Silva, RA Fonseca, K Glize, MF Kasim, A Savin, R Aboushelbaya, MW Mayr, B Spiers, RHW Wang, R Bingham, RMGM Trines, PA Norreys


Optimisation of confinement in a fusion reactor using a nonlinear turbulence model

JOURNAL OF PLASMA PHYSICS 84 (2018) ARTN 905840208

EG Highcock, NR Mandell, M Barnes, W Dorland


Cosmic-ray acceleration by relativistic shocks: limits and estimates

Monthly Notices of the Royal Astronomical Society 473 (2018) 2364-2371

AR Bell, AT Araudo, JH Matthews, KM Blundell


Generation of Internal Waves by Buoyant Bubbles in Galaxy Clusters and Heating of Intracluster Medium

Monthly Notices of the Royal Astronomical Society Blackwell Publishing Inc. (2018)

C Zhang, E Churazov, AA Schekochihin

Buoyant bubbles of relativistic plasma in cluster cores plausibly play a key role in conveying the energy from a supermassive black hole to the intracluster medium (ICM) - the process known as radio-mode AGN feedback. Energy conservation guarantees that a bubble loses most of its energy to the ICM after crossing several pressure scale heights. However, actual processes responsible for transferring the energy to the ICM are still being debated. One attractive possibility is the excitation of internal waves, which are trapped in the cluster's core and eventually dissipate. Here we show that a sufficient condition for efficient excitation of these waves in stratified cluster atmospheres is flattening of the bubbles in the radial direction. In our numerical simulations, we model the bubbles phenomenologically as rigid bodies buoyantly rising in the stratified cluster atmosphere. We find that the terminal velocities of the flattened bubbles are small enough so that the Froude number ${\rm Fr}\lesssim 1$. The effects of stratification make the dominant contribution to the total drag force balancing the buoyancy force. In particular, clear signs of internal waves are seen in the simulations. These waves propagate horizontally and downwards from the rising bubble, spreading their energy over large volumes of the ICM. If our findings are scaled to the conditions of the Perseus cluster, the expected terminal velocity is $\sim100-200{\,\rm km\,s^{-1}}$ near the cluster cores, which is in broad agreement with direct measurements by the Hitomi satellite.


Reconstruction of a direction-dependent primordial power spectrum from Planck CMB data

Journal of Cosmology and Astroparticle Physics 2018 (2018)

A Durakovic, P Hunt, S Mukherjee, S Sarkar, T Souradeep

© 2018 IOP Publishing Ltd and Sissa Medialab. We consider the possibility that the primordial curvature perturbation is direction-dependent. To first order this is parameterised by a quadrupolar modulation of the power spectrum and results in statistical anisotropy of the CMB, which can be quantified using 'bipolar spherical harmonics'. We compute these for the Planck DR2-2015 SMICA map and estimate the noise covariance from Planck Full Focal Plane 9 simulations. A constant quadrupolar modulation is detected with 2.2 σ significance, dropping to 2σ when the primordial power is assumed to scale with wave number k as a power law. Going beyond previous work we now allow the spectrum to have arbitrary scale-dependence. Our non-parametric reconstruction then suggests several spectral features, the most prominent at k ∼ 0.006 Mpc-1. When a constant quadrupolar modulation is fitted to data in the range 0.005 ≤ k/Mpc-1≤ 0.008, its preferred directions are found to be related to the cosmic hemispherical asymmetry and the CMB dipole. To determine the significance we apply two test statistics to our reconstructions of the quadrupolar modulation from data, against reconstructions of realisations of noise only. With a test statistic sensitive only to the amplitude of the modulation, the reconstructions from the multipole range 30 ≤ ℓ ≤ 1200 are unusual with 2.1σ significance. With the second test statistic, sensitive also to the direction, the significance rises to 6.9σ. Our approach is easily generalised to include other data sets such as polarisation, large-scale structure and forthcoming 21-cm line observations which will enable these anomalies to be investigated further.


COSMOS2015 photometric redshifts probe the impact of filaments on galaxy properties

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 473 (2018) 5437-5458

C Laigle, C Pichon, S Arnouts, HJ McCracken, Y Dubois, J Devriendt, A Slyz, D Le Borgne, A Benoit-Levy, HS Hwang, O Ilbert, K Kraljic, N Malavasi, C Park, D Vibert

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