(OV/P-3) Overview of the Globus-M Spherical Tokamak Results

V.K. Gusev1), B.B. Ayushin1), F.V. Chernyshev1), I.N. Chugunov1), V.V. Dyachenko1), L.A. Esipov1), D.B. Gin1), V.E. Golant1), S.A. Khitrov1), N.A. Khromov1), S.V. Krikunov1), G.S. Kurskiev1), M.M. Larionov1), R.G. Levin1), V.B. Minaev1), E.E. Mukhin1), A.N. Novokhatskii1), M.I. Patrov1), Yu.V. Petrov1), K.A. Podushnikova1), V.V. Rozhdestvensky1), N.V. Sakharov1), O.N. Shcherbinin1), A.E. Shevelev1), S.Yu. Tolstyakov1), V.I. Varfolomeev1), M.I. Vildjunas1), A.V. Voronin1), V.G. Kapralov2), I.V. Miroshnikov2), V.A. Rozhansky2), I.Yu. Senichenkov2), A.S. Smirnov2), I.Yu. Veselova2), S.E. Bender3), V.A. Belyakov3), Yu.A. Kostsov3), A.B. Mineev3), V.I. Vasiliev3), E.A. Kuznetsov4), V.N. Scherbitskii4), V.A. Yagnov4), A.G. Barsukov5), V.V. Kuznetsov5), V.M. Leonov5), A.A. Panasenkov5), G.N. Tilinin5), E.G. Zhilin6)
1) A.F. Ioffe Physico-Technical Institute, St. Petersburg, Russian Federation
2) St.-Petersburg State Polytechnical University, St. Petersburg, Russia
3) D.V. Efremov Institute of Electrophysical Apparatus, St. Petersburg, Russia
4) SSC RF TRINITI, Moscow region, Russia
5) NFI RRC Kurchatov Institute, Moscow, Russia
6) Ioffe Fusion Technology Ltd., St. Petersburg, Russia

Abstract.  A diminishing of impurities concentration in the discharge and the loop voltage decrease was achieved in the Globus-M spherical tokamak as a result of technological improvements. During experiments on density limit investigation in OH and NBI heating regimes the record average density in 0.4T magnetic field was reached in excess of 1.1×1020m-3 with gas puff supply only. The role of core long wave MHD fluctuations and their coupling with peripherial modes is outlined. Greenwald limit was achieved. The NBI fast particles slowing down spectrum was measured and found to be in agreement with classical Coulomb scattering theory. During NBI regimes with low target plasma density with overheated ions and high density with features of electron heating were obtained and studied. The fundamental harmonic ICR heating of hydrogen “minority” in deuterium plasma showed that the heating efficiency is relatively high and is improving with hydrogen concentration increase in the range of 10-70%. The role of the second harmonic is clarified. Plasma jet injection into Globus-M with a double-stage plasma gun showed that jet penetrated into the plasma as a time-of-flight recombined dense flux of neutrals. First numerical simulations of jet interaction with core plasma were done and showed that jet could penetrate beyond the separatrix. This doesn’t contradict interferometric and local density measurements performed by Thomson scattering.

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