Confirmation of the topology of the Wendelstein 7-X magnetic field to better than 1:100,000
Authors: Pedersen T. Sunn , Otte M. , Lazerson S. , Helander P. , Bozhenkov S. , Biedermann C. , Klinger T. , Wolf R. C. , Bosch H. -S. ,   The Wendelstein 7-X Team, Abramovic Ivana , Äkäslompolo Simppa , Aleynikov Pavel , Aleynikova Ksenia , Ali Adnan , Alonso Arturo , Anda Gabor , Andreeva Tamara , Ascasibar Enrique , Baldzuhn Jürgen , Banduch Martin , Barbui Tullio , Beidler Craig , Benndorf Andree , Beurskens Marc , Biel Wolfgang , Birus Dietrich , Blackwell Boyd , Blanco Emilio , Blatzheim Marko , Bluhm Torsten , Böckenhoff Daniel , Bolgert Peter , Borchardt Matthias , Böttger Lukas-Georg , Brakel Rudolf , Brandt Christian , Bräuer Torsten , Braune Harald , Burhenn Rainer , Buttenschön Birger , Bykov Victor , Calvo Ivan , Cappa Alvaro , Carls Andre , de Carvalho Bernardo Brotas , Castejon Francisco , Cianciosa Mark , Cole Michael , Costea Stefan , Cseh Gabor , Czarnecka Agata , Da Molin Andrea , de la Cal Eduardo , de la Pena Angel , Degenkolbe Sven , Prakash Dhard Chandra , Dinklage Andreas , Dostal Marion , Drevlak Michael , Drewelow Peter , Drews Philipp , Dudek Andrzej , Durodie Frederic , Dzikowicka Anna , van Eeten Paul , Effenberg Florian , Endler Michael , Erckmann Volker , Estrada Teresa , Fahrenkamp Nils , Fellinger Joris , Feng Yühe , Figacz Waldemar , Ford Oliver , Fornal Tomasz , Frerichs Heinke , Fuchert Golo , Garcia-Munoz Manuel , Geiger Benedikt , Geiger Joachim , Gierse Niels , Gogoleva Alena , Goncalves Bruno , Gradic Dorothea , Grahl Michael , Groß Silvia , Grote Heinz , Grulke Olaf , Guerard Carlos , Haas Matthias , Harris Jeffrey , Hartfuß Hans- Jürgen , Hartmann Dirk , Hathiramani Dag , Hein Bernd , Heinrich Stefan , Henneberg Sophia , Hennig Christine , Hernandez Julio , Hidalgo Carlos , Hidalgo Ulises , Hirsch Matthias , Höfel Udo , Hölbe Hauke , Hölting Alf , Houry Michael , Huber Valentina , Ionita Codrina , Israeli Ben , Jablonski Slowomir , Jakubowski Marcin , van Vuuren Anton Jansen , Jenzsch Hartmut , Kaczmarczyk Jacek , Kallmeyer Johann-Peter , Kamionka Ute , Kasahara Hiroshi , Kenmochi Naoki , Kernbichler Winfried , Killer Carsten , Kinna David , Kleiber Ralf , Knauer Jens , Köchl Florian , Kocsis Gabor , Kolesnichenko Yaroslav , Könies Axel , König Ralf , Kornejew Petra , Köster Felix , Krämer-Flecken Andreas , Krampitz Rüdiger , Krawzyk Natalia , Kremeyer Thierry , Krychowiak Maciej , Ksiazek Ireneusz , Kubkowska Monika , Kühner Georg , Kurki-Suonio Taina , Kurz Peter , Küttler Katja , Kwak Sehyun , Landreman Matt , Langenberg Andreas , Lapayese Fernando , Laqua Heike , Laqua Heinrich-Peter , Laube Ralph , Laux Michael , Lentz Holger , Lewerentz Marc , Liang Yunfeng , Liu Shaocheng , Lobsien Jim-Felix , Cisquella Joaquim Loizu , Lopez-Bruna Daniel , Lore Jeremy , Lorenz Axel , Lutsenko Vadym , Maaßerg Henning , Maisano-Brown Jeanette , Marchuk Oleksandr , Marrelli Lionello , Marsen Stefan , Marushchenko Nikolai , Masuzaki Suguru , McCarthy Kieran , McNeely Paul , Medina Francisco , Milojevic Dusan , Mishchenko Alexey , Missal Bernd , Mittelstaedt Joseph , Mollen Albert , Moncada Victor , Mönnich Thomas , Moseev Dmitry , Nagel Michael , Naujoks Dirk , Neilson George Hutch , Neubauer Olaf , Neuner Ulrich , Ngo Tran-Thanh , Niemann Holger , Nührenberg Carolin , Nührenberg Jürgen , Ochando Marian , Ogawa Kunihiro , Ongena Jef , Oosterbeek Hans , Pablant Novimir , Pacella Danilo , Pacios Luis , Panadero Nerea , Pasch Ekkehard , Pastor Ignacio , Pavone Andrea , Pawelec Ewa , Pedrosa Angeles , Perseo Valeria , Peterson Byron , Pilopp Dirk , Pisano Fabio , Puiatti Maria Ester , Plunk Gabriel , Preynas Melanie , Proll Josefine , Sitjes Aleix Puig , Purps Frank , Rack Michael , Rahbarnia Kian , Riemann Jörg , Riße Konrad , Rong Peter , Rosenberger Joachim , Rudischhauser Lukas , Rummel Kerstin , Rummel Thomas , Runov Alexey , Rust Norbert , Ryc Leszek , Saitoh Haruhiko , Satake Shinsuke , Schacht Jörg , Schmitz Oliver , Schmuck Stefan , Schneider Bernd , Schneider Matthias , Schneider Wolfgang , Schrittwieser Roman , Schröder Michael , Schröder Timo , Schröder Ralf , Schumacher Hans Werner , Schweer Bernd , Seki Ryosuke , Sinha Priyanjana , Sipilae Seppo , Slaby Christoph , Smith Håkan , Sousa Jorge , Spring Anett , Standley Brian , Stange Torsten , von Stechow Adrian , Stephey Laurie , Stoneking Matthew , Stridde Uwe , Suzuki Yasuhiro , Svensson Jakob , Szabolics Tamas , Szepesi Tamas , Thomsen Henning , Travere Jean-Marcel , Traverso Peter , Mora Humberto Trimino , Tsuchiya Hayato , Tsuijmura Tohru , Turkin Yuriy , Valet Swetlana , van Milligen Boudewijn , Vela Luis , Velasco Jose-Luis , Vergote Maarten , Vervier Michel , Viebke Holger , Vilbrandt Reinhard , von Thun Christian Perez , Wagner Friedrich , Wang Erhui , Wang Nengchao , Warmer Felix , Wauters Tom , Wegener Lutz , Wegner Thomas , Weir Gavin , Wendorf Jörg , Wenzel Uwe , Werner Andreas , Wie Yanling , Wiegel Burkhard , Wilde Fabian , Windisch Thomas , Winkler Mario , Winters Victoria , Wright Adelle , Wurden Glen , Xanthopoulos Pavlos , Yamada Ichihiro , Yasuhara Ryo , Yokoyama Masayuki , Zhang Daihong , Zilker Manfred , Zimbal Andreas , Zocco Alessandro , Zoletnik Sandor 
Published: November 2016

Fusion energy research has in the past 40 years focused primarily on the tokamak concept, but recent advances in plasma theory and computational power have led to renewed interest in stellarators. The largest and most sophisticated stellarator in the world, Wendelstein 7-X (W7-X), has just started operation, with the aim to show that the earlier weaknesses of this concept have been addressed successfully, and that the intrinsic advantages of the concept persist, also at plasma parameters approaching those of a future fusion power plant. Here we show the first physics results, obtained before plasma operation: that the carefully tailored topology of nested magnetic surfaces needed for good confinement is realized, and that the measured deviations are smaller than one part in 100,000. This is a significant step forward in stellarator research, since it shows that the complicated and delicate magnetic topology can be created and verified with the required accuracy.