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Start Over Author "Imazawa R" Publisher american physical society
2 results on '"Imazawa R"'

1. Electron and Ion Heating Characteristics during Magnetic Reconnection in the MAST Spherical Tokamak.

Author

Tanabe, H., Yamada, T., Watanabe, T., Gi, K., Kadowaki, K., Inomoto, M., Imazawa, R., Gryaznevich, M., Michael, C., Crowley, B., Conway, N. J., Scanned, R., Harrison, J., Fitzgerald, I., Meakins, A., Hawkes, N., McClements, K. G., O'Gorman, T., Cheng, C. Z., and Ono, Y.

Subjects
*MAGNETIC reconnection, *ELECTRONS, *ASTROPHYSICS, *MAGNETOSPHERIC physics, *TOKAMAKS
Abstract

Electron and ion heating characteristics during merging reconnection start-up on the MAST spherical tokamak have been revealed in detail using a 130 channel yttrium aluminum garnet (YAG) and a 300 channel Ruby-Thomson scattering system and a new 32 chord ion Doppler tomography diagnostic. Detailed 2D profile measurements of electron and ion temperature together with electron density have been achieved for the first time and it is found that electron temperature forms a highly localized hot spot at the X point and ion temperature globally increases downstream. For the push merging experiment when the guide field is more than 3 times the reconnecting field, a thick layer of a closed flux surface form by the reconnected field sustains the temperature profile for longer than the electron and ion energy relaxation time ∼4-10 ms, both characteristic profiles finally forming a triple peak structure at the X point and downstream. An increase in the toroidal guide field results in a more peaked electron temperature profile at the X point, and also produces higher ion temperatures at this point, but the ion temperature profile in the downstream region is unaffected. [ABSTRACT FROM AUTHOR]

Published
2015
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2. Search for Gamma-Ray Spectral Lines from Dark Matter Annihilation up to 100 TeV toward the Galactic Center with MAGIC.

Author

Abe H, Abe S, Acciari VA, Aniello T, Ansoldi S, Antonelli LA, Arbet Engels A, Arcaro C, Artero M, Asano K, Baack D, Babić A, Baquero A, Barres de Almeida U, Barrio JA, Batković I, Baxter J, Becerra González J, Bednarek W, Bernardini E, Bernardos M, Berti A, Besenrieder J, Bhattacharyya W, Bigongiari C, Biland A, Blanch O, Bonnoli G, Bošnjak Ž, Burelli I, Busetto G, Carosi R, Carretero-Castrillo M, Ceribella G, Chai Y, Chilingarian A, Cikota S, Colombo E, Contreras JL, Cortina J, Covino S, D'Amico G, D'Elia V, Da Vela P, Dazzi F, De Angelis A, De Lotto B, Del Popolo A, Delfino M, Delgado J, Delgado Mendez C, Depaoli D, Di Pierro F, Di Venere L, Do Souto Espiñeira E, Dominis Prester D, Donini A, Dorner D, Doro M, Elsaesser D, Emery G, Fallah Ramazani V, Fariña L, Fattorini A, Font L, Fruck C, Fukami S, Fukazawa Y, García López RJ, Garczarczyk M, Gasparyan S, Gaug M, Giesbrecht Paiva JG, Giglietto N, Giordano F, Gliwny P, Godinović N, Green JG, Green D, Hadasch D, Hahn A, Hassan T, Heckmann L, Herrera J, Hrupec D, Hütten M, Imazawa R, Inada T, Iotov R, Ishio K, Jiménez Martínez I, Jormanainen J, Kerszberg D, Kobayashi Y, Kubo H, Kushida J, Lamastra A, Lelas D, Leone F, Lindfors E, Linhoff L, Lombardi S, Longo F, López-Coto R, López-Moya M, López-Oramas A, Loporchio S, Lorini A, Lyard E, Machado de Oliveira Fraga B, Majumdar P, Makariev M, Maneva G, Mang N, Manganaro M, Mangano S, Mannheim K, Mariotti M, Martínez M, Mas Aguilar A, Mazin D, Menchiari S, Mender S, Mićanović S, Miceli D, Miener T, Miranda JM, Mirzoyan R, Molina E, Mondal HA, Moralejo A, Morcuende D, Moreno V, Nakamori T, Nanci C, Nava L, Neustroev V, Nievas Rosillo M, Nigro C, Nilsson K, Nishijima K, Njoh Ekoume T, Noda K, Nozaki S, Ohtani Y, Oka T, Otero-Santos J, Paiano S, Palatiello M, Paneque D, Paoletti R, Paredes JM, Pavletić L, Persic M, Pihet M, Podobnik F, Prada Moroni PG, Prandini E, Principe G, Priyadarshi C, Puljak I, Rhode W, Ribó M, Rico J, Righi C, Rugliancich A, Sahakyan N, Saito T, Sakurai S, Satalecka K, Saturni FG, Schleicher B, Schmidt K, Schmuckermaier F, Schubert JL, Schweizer T, Sitarek J, Sliusar V, Sobczynska D, Spolon A, Stamerra A, Strišković J, Strom D, Strzys M, Suda Y, Surić T, Takahashi M, Takeishi R, Tavecchio F, Temnikov P, Terauchi K, Terzić T, Teshima M, Tosti L, Truzzi S, Tutone A, Ubach S, van Scherpenberg J, Vazquez Acosta M, Ventura S, Verguilov V, Viale I, Vigorito CF, Vitale V, Vovk I, Walter R, Will M, Wunderlich C, Yamamoto T, Zarić D, Hiroshima N, and Kohri K

Abstract

Linelike features in TeV γ rays constitute a "smoking gun" for TeV-scale particle dark matter and new physics. Probing the Galactic Center region with ground-based Cherenkov telescopes enables the search for TeV spectral features in immediate association with a dense dark matter reservoir at a sensitivity out of reach for satellite γ-ray detectors, and direct detection and collider experiments. We report on 223 hours of observations of the Galactic Center region with the MAGIC stereoscopic telescope system reaching γ-ray energies up to 100 TeV. We improved the sensitivity to spectral lines at high energies using large-zenith-angle observations and a novel background modeling method within a maximum-likelihood analysis in the energy domain. No linelike spectral feature is found in our analysis. Therefore, we constrain the cross section for dark matter annihilation into two photons to ⟨σv⟩≲5×10^{-28}  cm^{3} s^{-1} at 1 TeV and ⟨σv⟩≲1×10^{-25}  cm^{3} s^{-1} at 100 TeV, achieving the best limits to date for a dark matter mass above 20 TeV and a cuspy dark matter profile at the Galactic Center. Finally, we use the derived limits for both cuspy and cored dark matter profiles to constrain supersymmetric wino models.

Published
2023
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