Breakdown Phase in the GOLEM Tokamak and Its Impact on Plasma Performance
Keywords:GOLEM tokamak, breakdown, avalanche, particle losses, plasma parameters
The effect of the breakdown phase on subsequent plasma parameters in GOLEM tokamak is investigated remotely. The dependence of the breakdown voltage and the breakdown time on the time delay between the switchings-on of a toroidal magnetic field Bt and a toroidal electric field Et for different groups of the pressure magnitudes is built. The performed experiments have shown that, for GOLEM tokamak, the shorter the temporal delay, the better are the mean plasma parameters. In addition, the breakdown phase is discussed in more details. In the discussion, the avalanche phase of the breakdown is analyzed. The dominant mechanism of particle losses during the avalanche phase, future steps, and tasks are discussed and set. The experiments on studying the breakdown phase have been carried out remotely on GOLEM tokamak by undergraduate students of V.N. Karazin Kharkiv National University.
A. Raicu et al. The thermal ionization phase during the plasma formation in TM-1-MH tokamak. Czechoslovak J. Phys. 37 (7), 850 (1987).
H. Prinzler, P. Heymann, J. Stockel et al. Investigations of the start up phase in the TM-1-MH tokamak. Czechoslovak J. Phys. 34, 665 (1987).
P.K. Chattopadhyay, R. Pal, N.R. Ray, P.K. Gupta. Breakdown and preionization experiments in the SINP tokamak. Nuclear Fusion 36 (9), 1205 (1996).
J.F. Benesch. Breakdown in the PRETEXT Tokamak (Ph.D. Thesis Texas Univ., Austin. Dept. of Physics, 1981).
W. Jiang, Y. Peng, Y. Zhang, G. Lapenta. Numerical modeling of tokamak breakdown phase driven by pure Ohmic heating under ideal conditions. Nucl. Fus. 56 (12), 126017 (2016).
V. Svoboda et al. Remote operation of the GOLEM tokamak with hydrogen and helium plasmas. J. Phys.: Conf. Ser. 768, 1 (2016).
V. Svoboda et al. Multi-mode remote participation on the GOLEM tokamak. Fusion Engineering and Design 86, 1310 (2011).
J. Brotankova. Breakdown in the PRETEXT Tokamak (Ph.D. Thesis Institute of Plasma Physics., Prague. Dept. of Surface and Plasma Science, 2009).
T. Markovic. Measurement of Magnetic Fields on GOLEM Tokamak (Diploma. Czech Technical University in Prague., Prague. Dept. of Physics, 2012).
R. Papoular. The genesis of toroidal discharges. Nucl. Fus. 16, 37 (1976).
B. Lloyd, G.L. Jackson, T.S. Taylor, E.A. Lazarus, T.C. Luce, R Prater. Low voltage Ohmic and electron cyclotron heating assisted startup in DIII-D. Nucl. Fus. 31, 2031 (1991).
M. Valovic. Convective losses during current initiation in tokamaks. Nucl. Fus. 27, 599 (1987).
B. Lloyd, P.G. Carolan, C.D. Warrick. ECRH-assisted start-up in ITER. Plasma Physics and Controlled Fusion 38, 1627 (1996).
T. Markovic. 3D simulation of the stray magnetic field on GOLEM (private communication).
How to Cite
License to Publish the Paper
The corresponding author and the co-authors (hereon referred to as the Author(s)) of the paper being submitted to the Ukrainian Journal of Physics (hereon referred to as the Paper) from one side and the Bogolyubov Institute for Theoretical Physics, National Academy of Sciences of Ukraine, represented by its Director (hereon referred to as the Publisher) from the other side have come to the following Agreement:
1. Subject of the Agreement.
The Author(s) grant(s) the Publisher the free non-exclusive right to use the Paper (of scientific, technical, or any other content) according to the terms and conditions defined by this Agreement.
2. The ways of using the Paper.
2.1. The Author(s) grant(s) the Publisher the right to use the Paper as follows.
2.1.1. To publish the Paper in the Ukrainian Journal of Physics (hereon referred to as the Journal) in original language and translated into English (the copy of the Paper approved by the Author(s) and the Publisher and accepted for publication is a constitutive part of this License Agreement).
2.1.2. To edit, adapt, and correct the Paper by approval of the Author(s).
2.1.3. To translate the Paper in the case when the Paper is written in a language different from that adopted in the Journal.
2.2. If the Author(s) has(ve) an intent to use the Paper in any other way, e.g., to publish the translated version of the Paper (except for the case defined by Section 2.1.3 of this Agreement), to post the full Paper or any its part on the web, to publish the Paper in any other editions, to include the Paper or any its part in other collections, anthologies, encyclopaedias, etc., the Author(s) should get a written permission from the Publisher.
3. License territory.
The Author(s) grant(s) the Publisher the right to use the Paper as regulated by sections 2.1.1–2.1.3 of this Agreement on the territory of Ukraine and to distribute the Paper as indispensable part of the Journal on the territory of Ukraine and other countries by means of subscription, sales, and free transfer to a third party.
4.1. This Agreement is valid starting from the date of signature and acts for the entire period of the existence of the Journal.
5.1. The Author(s) warrant(s) the Publisher that:
– he/she is the true author (co-author) of the Paper;
– copyright on the Paper was not transferred to any other party;
– the Paper has never been published before and will not be published in any other media before it is published by the Publisher (see also section 2.2);
– the Author(s) do(es) not violate any intellectual property right of other parties. If the Paper includes some materials of other parties, except for citations whose length is regulated by the scientific, informational, or critical character of the Paper, the use of such materials is in compliance with the regulations of the international law and the law of Ukraine.
6. Requisites and signatures of the Parties.
Publisher: Bogolyubov Institute for Theoretical Physics, National Academy of Sciences of Ukraine.
Address: Ukraine, Kyiv, Metrolohichna Str. 14-b.
Author: Electronic signature on behalf and with endorsement of all co-authors.