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1. Multi-wavelength picture of the misaligned BL Lac object 3C 371

Author

Otero-Santos, J., Raiteri, C. M., Tramacere, A., Pedrosa, J. Escudero, Acosta-Pulido, J. A., Carnerero, M. I., Villata, M., Agudo, I., Rahimov, I. A., Andreeva, T. S., Ivanov, D. V., Marchili, N., Righini, S., Giroletti, M., Gurwell, M. A., Savchenko, S. S., Carosati, D., Chen, W. P., Kurtanidze, S. O., Joner, M. D., Semkov, E., Pursimo, T., Benítez, E., Damljanovic, G., Andreuzzi, G., Apolonio, G., Borman, G. A., Bozhilov, V., Galindo-Guil, F. J., Grishina, T. S., Hagen-Thorn, V. A., Hiriart, D., Hsiao, H. Y., Ibryamov, S., Ivanidze, R. Z., Kimeridze, G. N., Kopatskaya, E. N., Kurtanidze, O. M., Larionov, V. M., Larionova, E. G., Larionova, L. V., Minev, M., Morozova, D. A., Nikolashvili, M. G., Ovcharov, E., Sigua, L. A., Stojanovic, M., Troitskiy, I. S., Troitskaya, Yu. V., Tsai, A., Valcheva, A., Vasilyev, A. A., Vince, O., Zaharieva, E., and Zhovtan, A. V.

Subjects
Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Astrophysics of Galaxies
Abstract

The BL Lac object 3C 371 is one of the targets that are regularly monitored by the Whole Earth Blazar Telescope (WEBT) Collaboration to study blazar variability on both short and long timescales. We aim to evaluate the long-term multiwavelength (MWL) behaviour of 3C 371, comparing it with the results derived for its optical emission in our previous study. For this, we make use of the multi-band campaigns organized by the WEBT Collaboration in optical and radio between January 2018 and December 2020, and of public data from Swift and Fermi satellites and the MOJAVE Very Large Interferometry programme. We evaluate the variability shown by the source in each band with the amplitude variability quantification, as well as possible interband correlation using the z-Discrete Correlation Function. We also present a deep analysis of the optical-UV, X-ray and $\gamma$-ray spectral variability. With the MOJAVE data we perform a kinematics analysis, looking for components propagating along the jet, calculating its kinematics parameters. This set of parameters is later used for the interpretation of the source MWL behaviour, modelling the broadband spectral energy distribution (SED) of the source with theoretical blazar emission scenarios., Comment: Accepted in A&A, 23 pages, 15 figures

Published
2024

2. Multiwavelength variability of the blazar AO 0235+164

Author

Vlasyuk, V. V., Sotnikova, Yu. V., Volvach, A. E., Mufakharov, T. V., Kovalev, Yu. A., Spiridonova, O. I., Khabibullina, M. L., Kovalev, Yu. Yu., Mikhailov, A. G., Stolyarov, V. A., Kudryavtsev, D. O., Mingaliev, M. G., Razzaque, S., Semenova, T. A., Kudryashova, A. K., Bursov, N. N., Trushkin, S. A., Popkov, A. V., Erkenov, A. K., Rakhimov, I. A., Kharinov, M. A., Gurwell, M. A., Tsybulev, P. G., Moskvitin, A. S., Fatkhullin, T. A., Emelianov, E. V., Arshinova, A., Iuzhanina, K. V., Andreeva, T. S., Volvach, L. N., and Ghosh, A.

Subjects
Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Astrophysics of Galaxies
Abstract

We present a study of the multiwavelength (MW) variability of the blazar AO 0235+164 based on the radio-to-$\gamma$-ray data covering a long time period from 1997 to 2023. The radio data are represented by the 1-22 GHz measurements from the RATAN-600 radio telescope, the 5 and 8 GHz data from the RT-32 telescopes, and the 37 GHz data from the RT-22 telescope. The optical measurements in the $R$-band were collected with the 1-m Zeiss-1000 and 0.5-m AS-500/2 telescopes. Additionally we used the archive data at 230~GHz from the SMA and the $\gamma$-ray data in the 0.1-100 GeV band from the Fermi-LAT point source 4FGL-DR2 catalogue. The variability properties during four epochs containing major flares and one epoch of relatively low activity were analysed. A significant correlation ($\geq\!2\sigma$) between the radio, optical, and $\gamma$-ray bands is found for all these periods with time delays from 0 to 1.7 yrs. The relation between time delay and frequency is described by a linear law with a negative slope of -10 day/GHz. The discovered properties of MW variability for the low activity period and for flaring states suggest that the mechanisms dominating the radio-$\gamma$-ray variations are not substantially different. The detected quasi-periodic oscillations of about 6 and 2 years are tentative, as the time span of the observations includes fewer than 4 full cycles for the radio and optical data and only about 3 cycles for the Fermi-LAT data. The physical parameters of the radio jet were obtained using the Hedgehog model applied to the average radio spectrum of AO 0235+164 in the range 0.1-300 GHz. The effectiveness of replacing electrons with protons in the synchrotron radio emission of relativistic jets is shown for describing the nature of blazars and the generation of high energy neutrinos., Comment: Accepted 2024 October 30 for publication in MNRAS

Published
2024
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3. A wiggling filamentary jet at the origin of the blazar multi-wavelength behaviour

Author

Raiteri, C. M., Villata, M., Carnerero, M. I., Kurtanidze, S. O., Mirzaqulov, D. O., Benítez, E., Bonnoli, G., Carosati, D., Acosta-Pulido, J. A., Agudo, I., Andreeva, T. S., Apolonio, G., Bachev, R., Borman, G. A., Bozhilov, V., Brown, L. F., Carbonell, W., Casadio, C., Chen, W. P., Damljanovic, G., Ehgamberdiev, S. A., Elsaesser, D., Escudero, J., Feige, M., Fuentes, A., Gabellini, D., Gazeas, K., Giroletti, M., Grishina, T. S., Gupta, A. C., Gurwell, M. A., Hagen-Thorn, V. A., Hamed, G. M., Hiriart, D., Hodges, M., ivanidze, R. Z., Ivanov, D. V., Joner, M. D., Jorstad, S. G., Jovanovic, M. D., Kiehlmann, S., Kimeridze, G. N., Kopatskaya, E. N., Kovalev, Yu. A., Kovalev, Y. Y., Kurtanidze, O. M., Kurtenkov, A., Larionova, E. G., Lessing, A., Lin, H. C., López, J. M., Lorey, C., Ludwig, J., Marchili, N., Marchini, A., Marscher, A. P., Matsumoto, K., Max-Moerbeck, W., Mihov, B., Minev, M., Mingaliev, M. G., Modaressi, A., Morozova, D. A., Mortari, F., Mufakharov, T. V., Myserlis, I., Nikolashvili, M. G., Pearson, T. J., Popkov, A. V., Rahimov, I. A., Readhead, A. C. S., Reinhart, D., Reeves, R., Righini, S., Romanov, F. D., Savchenko, S. S., Semkov, E., Shishkina, E. V., Sigua, L. A., Slavcheva-Mihova, L., Sotnikova, Yu. V., Steineke, R., Stojanovic, M., Strigachev, A., Takey, A., Traianou, E., Troitskaya, Yu. V., Troitskiy, I. S., Tsai, A. L., Valcheva, A., Vasilyev, A. A., Verna, G., Vince, O., Vrontaki, K., Weaver, Z. R., Webb, J., Yuldoshev, Q. X., Zaharieva, E., and Zhovtan, A. V.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

Blazars are beamed active galactic nuclei known for their strong multi-wavelength variability on timescales from years down to minutes. We aim to investigate the suitability of the twisting jet model presented in previous works to explain the multi-wavelength behaviour of BL Lacertae, the prototype of one of the blazar classes. According to this model, the jet is inhomogeneous, curved, and twisting, and the long-term variability is due to changes in the Doppler factor due to variations in the orientation of the jet-emitting regions. We analysed optical data of the source obtained during monitoring campaigns organised by the Whole Earth Blazar Telescope (WEBT) in 2019-2022, together with radio data from the WEBT and other teams, and gamma-ray data from the Fermi satellite. In this period, BL Lacertae underwent an extraordinary activity phase, reaching its historical optical and gamma-ray brightness maxima. The application of the twisting jet model to the source light curves allows us to infer the wiggling motion of the optical, radio, and gamma-ray jet-emitting regions. The optical-radio correlation shows that the changes in the radio viewing angle follow those in the optical viewing angle by about 120 days, and it suggests that the jet is composed of plasma filaments, which is in agreement with some radio high-resolution observations of other sources. The gamma-ray emitting region is found to be co-spatial with the optical one, and the analysis of the gamma-optical correlation is consistent with both the geometric interpretation and a synchrotron self-Compton (SSC) origin of the high-energy photons. We propose a geometric scenario where the jet is made up of a pair of emitting plasma filaments in a sort of double-helix curved rotating structure, whose wiggling motion produces changes in the Doppler beaming and can thus explain the observed multi-wavelength long-term variability., Comment: In press for A&A

Published
2024
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12. Status and initial physics performance studies of the MPD experiment at NICA

Author

MPD Collaboration, Abgaryan, V., Kado, R. Acevedo, Afanasyev, S. V., Agakishiev, G. N., Alpatov, E., Altsybeev, G., Hernández, M. Alvarado, Andreeva, S. V., Andreeva, T. V., Andronov, E. V., Anfimov, N. V., Aparin, A. A., Astakhov, V. I., Atkin, E., Aushev, T., Averichev, G. S., Averyanov, A. V., Ayala, A., Babkin, V. A., Babutsidze, T., Balashov, I. A., Bancer, A., Barabanov, M. Yu., Baranov, D. A., Baranova, N., Barbashina, N., Baskakov, A. E., Batyuk, P. N., Bazhazhin, A. G., Baznat, D., Baznat, M., Bazylev, S. N., Beltran, L. G. E., Belyaev, A. V., Belyaev, S. E., Belyaeva, E. V., Benda, V., Bielewicz, M., Bietenholz, W., Blaschke, D., Blau, D., Bogdanova, G., Bogoslovsky, D. N., Boguslavsky, I. V., Boos, E., Botvina, A., Bravina, L., Bulychjov, S. A., Buryakov, M. G., Butenko, A. V., Butorin, A. V., Buzin, S. G., Bychkov, A., Bychkov, A. V., Cabellero, R. R., Arciniega, D. Chaires, Chalyshev, V. V., Chen, W., Chen, Z., Cheplakova, V. A., Chepurnov, V. F., Chepurnov, V. V., Cheremnova, M., Cheremukhina, G. A., Chlad, L., Chudoba, P., Chumakov, P. V., Cuautle, E., Czarnynoga, M., Dabrowska, B., Dąbrowski, D., Demanov, A., Dementyev, D. V., Deng, Z., Dmitriev, A. V., Dodokhov, V. Kh., Dolbilina, E. V., Dolbilov, A. G., Domínguez, I., Dominik, W., Donets, D. E., Dronik, V., Dubrovin, A. Yu., Dudziński, A., Dulov, P., Dunin, N. V., Dunin, V. B., Dyatlov, V., Dydyshko, V. F., Efremov, A. A., Egorov, D. S., Elsha, V. V., Emelyanov, A. E., Emelyanov, N. E., Ermakova, V. G., Eyyubova, G., Fang, D., Fateev, O. V., Fedin, O., Fedotov, Yu. I., Fedyunin, A. A., Feng, C., Feng, S., Feofilov, G. A., Filippov, I. A., Fischer, T., Formenko, K., Gaganova, M. A., Gandzhelashvili, T. T., Gavrishchuk, O. P., Geraksiev, N., Gerasimov, S. E., Gertsenberger, K. V., Golosov, O., Golovatyuk, V. M., Golubeva, M., Goncharov, I., Gorbunov, N. V., Grabowski, M., Grodzicka-Kobyłka, M., Grodzicki, K., Grzyb, J., Guber, F., Guirado, A., Guskov, A. V., Guzey, V., He, W., Rosas, L. A. Hernández, Huang, M., Huang, Y., Idczak, R., Idrisov, D., Igolkin, S. N., Ilieva, M., Isupov, A. Yu., Ivanishchev, D., Ivanov, A. V., Ivanytskyi, O., Ivashkin, A., Izvestnyy, A., Jaworska, E., Jiao, J., Kadochnikov, I., Kakurin, S. I., Kankiewicz, P., Kapishin, M. N., Karmanov, D., Karpushkin, N., Kartashova, L. A., Kashirin, E., Kasprowicz, G., Kasumov, Yu., Kechechyan, A. O., Kekelidze, G. D., Kekelidze, V. D., Khanzadeev, A., Kharlamov, P., Khilinova, O. A., Khodzhibagiyan, G. G., Khosravi, N., Khvorostukhin, A., Khyzhniak, Y., Kikvadze, V., Kireyeu, V. A., Kiryushin, Yu. T., Kiryutin, I. S., Kisiel, A., Klyuev, A., Klyukhin, V., Kochenda, L., Kodolova, O., Kolesnikov, V. I., Kolozhvari, A., Komarov, V. G., Kondratiev, V. P., Korolev, M., Korotkikh, V., Kotov, D., Kovalenko, S., Kovalenko, V. N., Kowalski, S., Kozlenko, N. A., Krakowiak, M., Kramarenko, V. A., Krasnova, L. M., Kravchov, P., Krechetov, Yu. F., Kruglova, I. V., Krylov, A. V., Krylov, V., Kryshen, E., Kryukov, A., Kubankin, A., Kugler, A., Kuich, M., Kukarnikov, S. I., Kuklin, S. N., Kukulin, V., Kuleshov, S., Kulikov, E. A., Kulikov, V. V., Kurepin, A., Kushpil, S., Kuzmin, V. S., Kvita, J., Lanskoy, D., Lashmanov, N. A., Ławryńczuk, M., Lazareva, T. V., Lednicky, R., Li, S., Li, Z., Litvinenko, A. G, Litvinenko, E. I., Litvinova, G. N., Liu, D., Liu, F., Livanov, A. N., Lobanov, V. I., Lobanov, Yu. Yu., Lobastov, S. P., Lokhtin, I., Lu, P., Lukstinsh, Yu. R., Luong, B. V., Łysakowski, B., Ma, Y., Machavariani, A., Madigozhin, D. T., Maksiak, B., Maksimenkova, V. I., Malakhov, A. I., Malayev, M., Maldonado, I., Maldonado, J. C., Malikov, I. V., Malinina, L., Maltsev, N. A., Maria, N. V., Shopova, M., Martemianov, M. A., Maslan, M., Matsyuk, M. A., Matulewicz, T., Melnikov, D. G., Merkin, M., Merts, S. P., Meshkov, I. N., Mianowski, S., Migulina, I. I., Mikhaylov, K. R., Milewicz-Zalewska, M., Minaev, Yu. I., Molokanova, N. A., Moreno-Barbosa, E., Morozov, S., Moshkin, A. A., Moshkovsky, I. V., Moskovsky, A. E., Movchan, S. A., Mudrokh, A. A., Mukhin, K. A., Murin, Yu. A., Musul'manbekov, Zh. Zh., Myalkovsky, V. V., Myktybekov, D., Paredes, L. L. Narvaez, Nauruzbaev, D. K., Nazarova, E. N., Nechaevsky, A. V., Nesterov, D. G., Nie, M., Nieto-Marín, P. A., Nigmatkulov, G., Nikitin, V. A., Nioradze, M., Niu, X., Nowak, W., Nozka, L., Oleks, I. A., Olshevsky, A. G., Orlov, O. E., Parfenov, P., Parzhitsky, S. S., Patiño, M. E., Pavlyukevich, V. A., Penkin, V. A., Peresedov, V. F., Peresunko, D., Peshekhonov, D. V., Petrov, V. A., Petrushanko, S., Petukhov, O., Piasecki, K., Pichugina, D. V., Piloyan, A., Pilyar, A. V., Piyadin, S. M., Plamowski, S., Platonova, M., Pluta, J., Potanina, A. E., Potrebenikov, Yu. K., Poźniak, K., Prokhorova, D. S., Prokofiev, N. A., Protoklitow, F., Prozorov, A., Pszczel, D., Puchkov, A. M, Pukhaeva, N., Puławski, S., Rakhmatullina, A. R., Herrera, L. F. Rebolledo, Reyna-Ortiz, V. Z., Riabov, V., Riabov, Yu., Ridinger, N. O., Rikhvitsky, V., Rodriguez-Cahuantzi, M., Rogachevsky, O. V., Rogov, V. Yu., Rokita, P., Romanenko, G., Romaniuk, R., Romanova, A., Rosłon, K., Rossler, T., Calderon, E. F. Rozas, Rufanov, I. A., Rumyantsev, M. M., Rustamov, A., Rybakov, A. A., Rybczyński, M., Rybka, D., Rymshina, A. A., Rzadkiewicz, J., Sadygov, Z. Ya. -O., Samsonov, V. A., Sandul, V. S., Sattarov, R., Savenkov, A. A., Schmidt, K., Seballos, S. S., Sedykh, S. A., Selyuzhenkov, I., Semchukova, T. V., Semenov, A. Yu., Semenova, I. A., Sergeev, S. V., Sergeeva, N. A., Serochkin, E. V., Seryakov, A. Yu., Shabunov, A. V., Shanidze, R., Shcheglova, L., Shchinov, B. G., Shen, C., Shen, Y., Sherbakov, A. N., Sheremetyev, A. D., Sheremetyeva, A. I., Shindin, R. A., Shipunov, A. V., Shitenkov, M. O., Shtejer, D. K., Shukla, U., Shunko, A. A., Shutov, A. V., Shutov, V. B., Sidorin, A. O., Skwira-Chalot, I., Slepnev, I. V., Slepnev, V. M., Slepov, I. P., Solnyshkin, Yu. A., Solomin, A., Solovyeva, T., Sorin, A. S., Starecki, T., Stefanek, G., Stepaniak, J., Streletskaya, E. A., Strikhanov, M., Strizh, T. A., Strizhak, A., Sukhov, N. V., Sukhovarov, S. I., Sun, X., Surkov, N. N., Suvarieva, D., Svalov, V. L., Świderski, L., Syntfeld-Każuch, A., Szcześniak, T., Szewiński, J., Tang, Z., Taranenko, A., Tarasov, N. A., Tcholakov, V., Tejeda-Muñoz, G., Tejeda-Yeomans, M. E., Terletskiy, A. V., Teryaev, O. V., Tikhomirov, V. V., Timoshenko, A. A., Tkachev, G. P., Toneev, V. D., Topilin, N. D., Traczyk, T., Tretyakova, T., Trubnikov, A. V., Trubnikov, G. V., Tyapkin, I. A., Udovenko, S. Yu., Poblete, P. A. Ulloa, Urbaniak, M., Urumov, V., Valenzuela-Cazares, L., Valiev, F. F., Vasendina, V. A., Vasiliev, I. N., Vasilyev, A., Vechernin, V. V., Vereshchagin, S. V., Vladimirova, N. N., Vlasov, N. V., Vodopyanov, A. S., Vokhmyanina, K., Volkov, V., Volodina, O. A., Voronin, A. A., Voronyuk, V., Wang, F., Wang, J., Wang, X., Wang, Y., Wieczorek, P., Wielanek, D., Włodarczyk, Z., Wójcik, K., Wu, K., Xiao, Z., Xu, Q., Yang, C., Yang, H., Yang, Q., Yarygin, G. A., Yordanova, L., Yu, T., Yuan, Z., Yurevich, V. I., Zabołotny, W., Zabrodin, E., Zaitseva, M. V., Saa, J. A. Zamora, Zamyatin, N. I., Zaporozhets, S. A., Zarochentsev, A. K., Zepeda-Fernández, C. H., Zha, W., Zhalov, M., Zhang, Y., Zhang, Z., Zhao, C., Zherebchevsky, V. I., Zhezher, V. N., Zhong, C., Zhou, W., Zhu, X., Zinchenko, A. I., and Zinchenko, D. A.

Subjects
Physics - Instrumentation and Detectors, High Energy Physics - Experiment, Nuclear Experiment, Nuclear Theory
Abstract

The Nuclotron-base Ion Collider fAcility (NICA) is under construction at the Joint Institute for Nuclear Research (JINR), with commissioning of the facility expected in late 2022. The Multi-Purpose Detector (MPD) has been designed to operate at NICA and its components are currently in production. The detector is expected to be ready for data taking with the first beams from NICA. This document provides an overview of the landscape of the investigation of the QCD phase diagram in the region of maximum baryonic density, where NICA and MPD will be able to provide significant and unique input. It also provides a detailed description of the MPD set-up, including its various subsystems as well as its support and computing infrastructures. Selected performance studies for particular physics measurements at MPD are presented and discussed in the context of existing data and theoretical expectations., Comment: 53 pages, 68 figures, submitted as a Review article to EPJA

Published
2022
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23. Multiwavelength behaviour of the blazar 3C279: decade-long study from $\gamma$-ray to radio

Author

Larionov, V. M., Jorstad, S. G., Marscher, A. P., Villata, M., Raiteri, C. M., Smith, P. S., Agudo, I., Savchenko, S. S., Morozova, D. A., Acosta-Pulido, J. A., Aller, M. F., Aller, H. D., Andreeva, T. S., Arkharov, A. A., Bachev, R., Bonnoli, G., Borman, G. A., Bozhilov, V., Calcidese, P., Carnerero, M. I., Carosati, D., Casadio, C., Chen, W. -P., Damljanovic, G., Dementyev, A. V., Di Paola, A., Frasca, A., Fuentes, A., Gómez, J. L., Gónzalez-Morales, P., Giunta, A., Grishina, T. S., Gurwell, M. A., Hagen-Thorn, V. A., Hovatta, T., Ibryamov, S., Joshi, M., Kiehlmann, S., Kim, J. -Y., Kimeridze, G. N., Kopatskaya, E. N., Kovalev, Yu. A., Kovalev, Y. Y., Kurtanidze, O. M., Kurtanidze, S. O., Lähteenmäki, A., Lázaro, C., Larionova, L. V., Larionova, E. G., Leto, G., Marchini, A., Matsumoto, K., Mihov, B., Minev, M., Mingaliev, M. G., Mirzaqulov, D., Dimitrova, R. V. Muñoz, Myserlis, I., Nikiforova, A. A., Nikolashvili, M. G., Nizhelsky, N. A., Ovcharov, E., Pressburger, L. D., Rakhimov, I. A., Righini, S., Rizzi, N., Sadakane, K., Sadun, A. C., Samal, M. R., Sanchez, R. Z., Semkov, E., Sergeev, S. G., Sigua, L. A., Slavcheva-Mihova, L., Sola, P., Sotnikova, Yu. V., Strigachev, A., Thum, C., Traianou, E., Troitskaya, Yu. V., Troitsky, I. S., Tsybulev, P. G., Vasilyev, A. A., Vince, O., Weaver, Z. R., Williamson, K. E., and Zhekanis, G. V.

Subjects
Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Astrophysics of Galaxies
Abstract

We report the results of decade-long (2008-2018) $\gamma$-ray to 1 GHz radio monitoring of the blazar 3C 279, including GASP/WEBT, $\it{Fermi}$ and $\it{Swift}$ data, as well as polarimetric and spectroscopic data. The X-ray and $\gamma$-ray light curves correlate well, with no delay > 3 hours, implying general co-spatiality of the emission regions. The $\gamma$-ray-optical flux-flux relation changes with activity state, ranging from a linear to a more complex dependence. The behaviour of the Stokes parameters at optical and radio wavelengths, including 43 GHz VLBA images, supports either a predominantly helical magnetic field or motion of the radiating plasma along a spiral path. Apparent speeds of emission knots range from 10 to 37c, with the highest values requiring bulk Lorentz factors close to those needed to explain $\gamma$-ray variability on very short time scales. The Mg II emission line flux in the `blue' and `red' wings correlates with the optical synchrotron continuum flux density, possibly providing a variable source of seed photons for inverse Compton scattering. In the radio bands we find progressive delays of the most prominent light curve maxima with decreasing frequency, as expected from the frequency dependence of the $\tau=1$ surface of synchrotron self-absorption. The global maximum in the 86 GHz light curve becomes less prominent at lower frequencies, while a local maximum, appearing in 2014, strengthens toward decreasing frequencies, becoming pronounced at $\sim5$ GHz. These tendencies suggest different Doppler boosting of stratified radio-emitting zones in the jet., Comment: 21 pages, 18 figures, accepted for publication in MNRAS

Published
2020
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31. Rapid quasi-periodic oscillations in the relativistic jet of BL Lacertae

Author

Jorstad, S. G., Marscher, A. P., Raiteri, C. M., Villata, M., Weaver, Z. R., Zhang, H., Dong, L., Gómez, J. L., Perel, M. V., Savchenko, S. S., Larionov, V. M., Carosati, D., Chen, W. P., Kurtanidze, O. M., Marchini, A., Matsumoto, K., Mortari, F., Aceti, P., Acosta-Pulido, J. A., Andreeva, T., Apolonio, G., Arena, C., Arkharov, A., Bachev, R., Banfi, M., Bonnoli, G., Borman, G. A., Bozhilov, V., Carnerero, M. I., Damljanovic, G., Ehgamberdiev, S. A., Elsässer, D., Frasca, A., Gabellini, D., Grishina, T. S., Gupta, A. C., Hagen-Thorn, V. A., Hallum, M. K., Hart, M., Hasuda, K., Hemrich, F., Hsiao, H. Y., Ibryamov, S., Irsmambetova, T. R., Ivanov, D. V., Joner, M. D., Kimeridze, G. N., Klimanov, S. A., Knött, J., Kopatskaya, E. N., Kurtanidze, S. O., Kurtenkov, A., Kuutma, T., Larionova, E. G., Leonini, S., Lin, H. C., Lorey, C., Mannheim, K., Marino, G., Minev, M., Mirzaqulov, D. O., Morozova, D. A., Nikiforova, A. A., Nikolashvili, M. G., Ovcharov, E., Papini, R., Pursimo, T., Rahimov, I., Reinhart, D., Sakamoto, T., Salvaggio, F., Semkov, E., Shakhovskoy, D. N., Sigua, L. A., Steineke, R., Stojanovic, M., Strigachev, A., Troitskaya, Y. V., Troitskiy, I. S., Tsai, A., Valcheva, A., Vasilyev, A. A., Vince, O., Waller, L., Zaharieva, E., and Chatterjee, R.

Published
2022
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37. Demonstration of reduced neoclassical energy transport in Wendelstein 7-X

Author

Beidler, C. D., Smith, H. M., Alonso, A., Andreeva, T., Baldzuhn, J., Beurskens, M. N. A., Borchardt, M., Bozhenkov, S.A., Brunner, K.J., Damm, H., Drevlak, M., Ford, O.P., Fuchert, G., Geiger, J., Helander, P., Hergenhahn, U., and Hirsch, M.

Subjects
Energy transformation -- Research, Stellarators -- Usage, Environmental issues, Science and technology, Zoology and wildlife conservation
Abstract

Research on magnetic confinement of high-temperature plasmas has the ultimate goal of harnessing nuclear fusion for the production of electricity. Although the tokamak.sup.1 is the leading toroidal magnetic-confinement concept, it is not without shortcomings and the fusion community has therefore also pursued alternative concepts such as the stellarator. Unlike axisymmetric tokamaks, stellarators possess a three-dimensional (3D) magnetic field geometry. The availability of this additional dimension opens up an extensive configuration space for computational optimization of both the field geometry itself and the current-carrying coils that produce it. Such an optimization was undertaken in designing Wendelstein 7-X (W7-X).sup.2, a large helical-axis advanced stellarator (HELIAS), which began operation in 2015 at Greifswald, Germany. A major drawback of 3D magnetic field geometry, however, is that it introduces a strong temperature dependence into the stellarator's non-turbulent 'neoclassical' energy transport. Indeed, such energy losses will become prohibitive in high-temperature reactor plasmas unless a strong reduction of the geometrical factor associated with this transport can be achieved; such a reduction was therefore a principal goal of the design of W7-X. In spite of the modest heating power currently available, W7-X has already been able to achieve high-temperature plasma conditions during its 2017 and 2018 experimental campaigns, producing record values of the fusion triple product for such stellarator plasmas.sup.3,4. The triple product of plasma density, ion temperature and energy confinement time is used in fusion research as a figure of merit, as it must attain a certain threshold value before net-energy-producing operation of a reactor becomes possible.sup.1,5. Here we demonstrate that such record values provide evidence for reduced neoclassical energy transport in W7-X, as the plasma profiles that produced these results could not have been obtained in stellarators lacking a comparably high level of neoclassical optimization. Previously documented record values of the fusion triple product in the stellarator Wendelstein 7-X are shown to be evidence for reduced neoclassical energy transport in this optimized device., Author(s): C. D. Beidler [sup.1] , H. M. Smith [sup.1] , A. Alonso [sup.2] , T. Andreeva [sup.1] , J. Baldzuhn [sup.1] , M. N. A. Beurskens [sup.1] , M. [...]

Published
2021
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41. Overview of the first Wendelstein 7-X long pulse campaign with fully water-cooled plasma facing components.

Author

Grulke, O., Albert, C., Alcuson Belloso, J.A., Aleynikov, P., Aleynikova, K., Alonso, A., Anda, G., Andreeva, T., Arvanitou, M., Ascasibar, E., Aymerich, E., Avramidis, K., Bähner, J.-P., Baek, S.-G., Balden, M., Baldzuhn, J., Ballinger, S., Banduch, M., Bannmann, S., and Bañón Navarro, A.

Subjects
ELECTRON cyclotron resonance heating, COOLING of water, PLASMA beam injection heating, HEAT flux, ENTHALPY, PLASMA heating, MAGNETIC measurements
Abstract

After a long device enhancement phase, scientific operation resumed in 2022. The main new device components are the water cooling of all plasma facing components and the new water-cooled high heat flux divertor units. Water cooling allowed for the first long-pulse operation campaign. A maximum discharge length of 8 min was achieved with a total heating energy of 1.3 GJ. Safe divertor operation was demonstrated in attached and detached mode. Stable detachment is readily achieved in some magnetic configurations but requires impurity seeding in configurations with small magnetic pitch angle within the edge islands. Progress was made in the characterization of transport mechanisms across edge magnetic islands: Measurement of the potential distribution and flow pattern reveals that the islands are associated with a strong poloidal drift, which leads to rapid convection of energy and particles from the last closed flux surface into the scrape-off layer. Using the upgraded plasma heating systems, advanced heating scenarios were developed, which provide improved energy confinement comparable to the scenario, in which the record triple product for stellarators was achieved in the previous operation campaign. However, a magnetic configuration-dependent critical heating power limit of the electron cyclotron resonance heating was observed. Exceeding the respective power limit leads to a degradation of the confinement. [ABSTRACT FROM AUTHOR]

Published
2024
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44. Achieving stationary high performance plasmas at Wendelstein 7-X

Author

Langenberg, A., Warmer, F., Fuchert, G., Ford, O., Bozhenkov, S., Andreeva, T., Lazerson, S., Pablant, N. A., Gonda, T., Beurskens, M. N.A., Brunner, K. J., Buttenschön, B., Dinklage, A., Hartmann, D., Knauer, J., Marchuk, O., Pasch, E., Reimold, F., Stange, T., Wegner, Th, Grulke, O., Wolf, R. C., Langenberg, A., Warmer, F., Fuchert, G., Ford, O., Bozhenkov, S., Andreeva, T., Lazerson, S., Pablant, N. A., Gonda, T., Beurskens, M. N.A., Brunner, K. J., Buttenschön, B., Dinklage, A., Hartmann, D., Knauer, J., Marchuk, O., Pasch, E., Reimold, F., Stange, T., Wegner, Th, Grulke, O., and Wolf, R. C.

Abstract

This work reports on recent results on the search for high performance plasma scenarios at the magnetically confined stellarator fusion device Wendelstein 7-X. In four new designed scenarios, the development from transient toward stationary plasmas of improved performance has been realized. In particular, a high performance duration of up to 5 s, an energy confinement time of 0.3 s, a diamagnetic energy of 1.1 MJ, a central ion temperature of 2.2 keV, and a fusion triple product of 3.4 × 10 19 m − 3 · keV · s have been achieved, and previously observed limitations of the machine have been overcome, regarding both the performance and its duration. The two main experimental techniques for stationary high performance are neutral beam injection core fueling on the one hand and the use of a magnetic field configuration with internal islands on the other hand. Two of the developed scenarios are expected to be extendable straightforward toward a duration of several tens of seconds, making use of the long pulse operation capabilities of W7-X.

Published
2024

46. Radial localization of electron temperature pedestal and ELM-like events using ECE measurements at Wendelstein 7-X

Author

Chaudhary N., Hirsch M., Andreeva T., Geiger J., Hoefel U., Rahbarnia K., Wurden G. A., and Wolf R. C.

Subjects
Physics, QC1-999
Abstract

A magnetic configuration scan was performed at Wendelstein 7-X stellarator by varying the rotational transform to analyze the plasma confinement for magnetic configurations with different edge magnetic island locations and sizes. For the magnetic configurations, where the 5/5 island chain was moved inside the last closed flux surface, it was observed with electron cyclotron emission measurements that an electron temperature, Te, pedestal develops in the plasma buildup phase and followed by the edge localized mode (ELM)-like crashes. From the mapping of the island to the plasma radius from HINT equilibrium, it was found that the Te pedestal is formed at the island location on the high field side of the plasma. The ELM-like crashes occur at the location of the pedestal and the transport barrier is broken typically with an energy loss of 3-4% during a single ELM-like event. The frequency and the amplitude of the ELM-like crashes were observed to be changing with island size, plasma heating power and density. Additionally during the plasma decay, after the heating was switched-off, a transition to degraded plasma confinement state was observed with changed Te profile gradients, faster decay rate of diamagnetic energy, and increased H-alpha levels.

Published
2023
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49. Peripubertal Serum Dioxin Concentrations and Sperm Methylome of Young Russian Adults

Author

Sergeyev, O., primary, Shershebnev, A., additional, Medvedeva, Y., additional, Suvorov, A., additional, Wu, H., additional, Goltsov, A., additional, Loukianov, E., additional, Andreeva, T., additional, Gusev, F., additional, Manakhov, F., additional, Smigulina, L., additional, Logacheva, M., additional, Shtratnikova, V., additional, Kuznetsova, I., additional, Speranskiy-Podobed, P., additional, Burns, J. S., additional, Williams, P. L., additional, Korrick, S., additional, Lee, M. M., additional, Rogaev, E., additional, Hauser, R., additional, and Pilsner, J. R., additional

Published
2021
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