Tokamak Chauffage Alfvén Brésilien Explained

The Tokamak Chauffage Alfvén Brésilien (TCABR) is a tokamak situated at the University of São Paulo (USP), Brazil.^{[1] [2]} TCABR is the largest tokamak in the southern hemisphere and one of the magnetic-confinement devices committed to advancing scientific knowledge in fusion power.

History

TCABR was originally designed and constructed in Switzerland, at the École Polytechnique Fédérale de Lausanne (EPFL), and operated there from 1980 until 1992, under the name of Tokamak Chauffage Alfvén (TCA). The main focus of TCA was to assess and enhance plasma heating with Alfvén waves. A couple of years later, the machine was transferred to USP, passing through an upgrade and adding Brésilien to its name. The operation of TCABR began in 1999.

Properties

The TCABR plasma is made of hydrogen and has a circular format.^[3] In general, its discharges are ohmically heated and the plasma current in TCABR reaches up to

I _{P} \leq 100 kA . The minor and major radii of TCABR are respectively a =18 . 0 cm and R =61 . 5 cm , giving an aspect ratio of A = R/a =3 . 4 . The TCABR central electron temperature is around k _{B} T _{e} \leq 650 eV (i.e., T _{e} \sim 6 x 10 ^{6} K ) and its mean electron density is 0 . 9 \leq\bar{n} _{e0} \leq 3 , in units of 10 ^{19} m ^{-3} . Other parameters of TCABR include the toroidal magnetic field, B _{0} \sim 1 . 1 T , the hydrogen filling pressure, P _{H} \simeq 3 x 10 ^{-4} Pa , a discharge duration of T _{D} \simeq 100 ms , and a steady-phase duration around T\leq 60 ms .

Parameters of TCABR^[4] !Parameter!Symbol!Value

Plasma format		Circular
Plasma composition	H	Hydrogen
Major radius	R _{0}	61 . 5 cm
Minor radius	a	18 . 0 cm
Aspect ratio (R _{0/a} )	A	3 . 4
Plasma current	I _{p}	\leq 100 kA
Central (or toroidal) magnetic field	B _{0}	\sim 1 . 1 T
Line-averaged electronic density	\overline{n} _{e0}	0 . 9 \sim 3 x 10 ^{19} m ^{-3}
Central electronic temperature	k _{BT} _{e0}	\sim 0 . 5 keV
Hydrogen filling pressure	P _{H}	1 \sim 3 x 10 ^{-2} Pa
Discharge duration	T _{D}	\simeq 100 ms
Duration of the steady phase	T	\leq 60 ms

Research program

The current purpose of the TCABR tokamak includes the study of Alfvén waves,^{[5] [6]} but is not restricted to it. Other research areas are (i) the characterization of magnetohydrodynamic (MHD) instabilities,^[7] (ii) the study of high-confinement regimes induced by electrical polarization of external electrodes in the plasma edge,^[8] (iii) the investigation of edge turbulence,^[9] and (iv) the study of plasma poloidal and toroidal rotation using optical diagnostics.^{[10] [11]} The TCABR team is also associated with a theoretical group focused on investigating instabilities and transport barriers in tokamaks and dynamical systems.^{[12] [13]}

An upgrade in the TCABR is also being conducted.^{[14] [15] [16]} A set of 108 RMP coils will be installed to control and study edge localized modes (ELMs). New shaping coils will be added, allowing great flexibility in plasma configurations (e.g. single null, double null, snowflake, and negative triangularity configurations). The vacuum-vessel inner wall of TCABR will receive graphite tiles to decrease impurity deposition and energy loss in the plasma.

Notes and References

1. Galvão . R M O. . Amador . C H S. . Baquero . W A H. . Borges . F. . Caldas . I. L. . Cuevas . N A M. . Duarte . V. N. . Elfimov . A. G. . Elizondo . J. I. . Fonseca . A M M. . Germano . T. M. . 2015 . Report on recent results obtained in TCABR . Journal of Physics: Conference Series . 591 . 1 . 012001 . 2015JPhCS.591a2001G . 10.1088/1742-6596/591/1/012001 . Grenfell . G. G. . Guimarães-Filho . Z. O. . Jeronimo . J. L. . Kuznetsov . Yu K. . Manrique . M A M. . Nascimento . I. C. . Pires . C J A. . Puglia . P G P. . Reis . A. P. . Ronchi . G. . Ruchko . L. F. . De Sá . W. P. . Sgalla . R J F. . Sanada . E. K. . Severo . J H F. . Theodoro . V. C. . Toufen . D. L.. 124858345 . free .
2. Web site: de Sá . Wanderley Pires . TCABR Wiki . 6 June 2022.
3. Grenfell . G. G. . Nascimento . I. C. . Oliveira . D. S. . Guimarães-Filho . Z. O. . Elizondo . J. I. . Reis . A. P. . Galvão . R. M. O. . Baquero . W. A. H. . Oliveira . A. M. . Ronchi . G. . De Sá . W. P. . 2018 . H-mode access and the role of spectral shift with electrode biasing in the TCABR tokamak . Physics of Plasmas . 25 . 7 . 072301 . 2018PhPl...25g2301G . 10.1063/1.5029561 . Severo . J. H. F. . T CABR Team . 125657283.
4. Estudo de perfis de pressão no Tokamak TCABR . Universidade de São Paulo . 2017-03-02 . São Paulo . Doutorado em Física . 10.11606/t.43.2017.tde-22022017-125032 . pt . Gilson . Ronchi. free .
5. Ruchko . L.F. . Ozono . E. . Galvão . R.M.O. . Nascimento . I.C. . Degasperi . F.T. . Lerche . E. . 1998 . Advanced antenna system for Alfvén wave plasma heating and current drive in TCABR tokamak . Fusion Engineering and Design . 43 . 15–28 . 10.1016/S0920-3796(98)00260-9.
6. Elfimov . A. G. . 2009 . Kinetic ion effect on geodesic acoustic Alfvén modes in tokamaks . Physics of Plasmas . 16 . 3 . 034501 . 2009PhPl...16c4501E . 10.1063/1.3081547.
7. Nascimento . I.C. . Kuznetsov . Yu.K. . Guimarães-Filho . Z.O. . El Chamaa-Neto . I. . Usuriaga . O. . Fonseca . A.M.M. . Galvão . R.M.O. . Caldas . I.L. . Severo . J.H.F. . Semenov . I.B. . Ribeiro . C. . 2007 . Suppression and excitation of MHD activity with an electrically polarized electrode at the TCABR tokamak plasma edge . Nuclear Fusion . 47 . 11 . 1570–1576 . 2007NucFu..47.1570N . 10.1088/0029-5515/47/11/019 . Heller . M.V.P. . Bellintani . V. . Elizondo . J.I. . Sanada . E.. 54829018 .
8. Nascimento . I.C . Kuznetsov . Y.K . Severo . J.H.F . Fonseca . A.M.M . Elfimov . A. . Bellintani . V. . Machida . M. . Heller . M.V.A.P . Galvão . R.M.O . Sanada . E.K . Elizondo . J.I . 2005 . Plasma confinement using biased electrode in the TCABR tokamak . Nuclear Fusion . 45 . 8 . 796–803 . 2005NucFu..45..796N . 10.1088/0029-5515/45/8/005. 56342265 .
9. Guimarães-Filho . Z.O. . Caldas . I.L. . Viana . R.L. . Kurths . J. . Nascimento . I.C. . Kuznetsov . Yu.K. . 2008 . Recurrence quantification analysis of electrostatic fluctuations in fusion plasmas . Physics Letters A . 372 . 7 . 1088–1095 . 2008PhLA..372.1088G . 10.1016/j.physleta.2007.07.088.
10. Severo . J.H.F . Nascimento . I.C . Tsypin . V.S . Galvão . R.M.O . 2003 . Plasma residual rotation in the TCABR tokamak . Nuclear Fusion . 43 . 10 . 1047–1056 . 2003NucFu..43.1047S . 10.1088/0029-5515/43/10/005. 250738978 .
11. Severo . J H F. . Canal . G. P. . Ronchi . G. . Andrade . N. B. . Fernandes . T. . Ikeda . M. Y. . Collares . M. P. . Galvão . R M O. . Nascimento . I. C. . Tendler . M. . 2021 . Overview of plasma rotation studies on the TCABR tokamak . Plasma Physics and Controlled Fusion . 63 . 7 . 075001 . 2021PPCF...63g5001S . 10.1088/1361-6587/abf955 . 235293558.
12. Marcus . F. A. . Caldas . I. L. . Guimarães-Filho . Z. O. . Morrison . P. J. . Horton . W. . Kuznetsov . Yu. K. . Nascimento . I. C. . 2008 . Reduction of chaotic particle transport driven by drift waves in sheared flows . Physics of Plasmas . 15 . 11 . 112304 . 2008PhPl...15k2304M . 10.1063/1.3009532.
13. Web site: de Sousa . Meirielen Caetano . Medeiros . Everton . Caldas . Iberê Luiz . 6 June 2022 . Website of the Oscillation Control Group .
14. Santos . A.O. . Komatsu . W. . Canal . G.P. . Severo . J.H.F. . De Sá . W.P. . Kassab . F. . Ferreira . J.G. . De Andrade . M.C.R. . Piqueira . J.R.C. . Nascimento . I.C. . Galvão . R.M.O. . 2020 . Development of high-current power supplies for the TCABR tokamak . Fusion Engineering and Design . 159 . 111698 . 10.1016/j.fusengdes.2020.111698 . 224884509.
15. Web site: Canal . G. P. . 6 June 2022 . An overview of the upgrade of the TCABR tokamak . 12th IAEA Technical Meeting on Control, Data Acquisition and Remote Participation for Fusion Research (2019).
16. Web site: Canal . G. P. . 6 June 2022 . Modernização do tokamak TCABR para estudos de supressão de ELMs por campos RMP . Comissão Nacional de Energia Nuclear, 1o Seminário Nacional de Fusão Nuclear (2021)..