TJ-K

The TJ-K device is a torsatron with a single helical coil (l=1, m=6).

History

TJ-K was originally named TJ-IU, and was constructed at CIEMAT in Madrid, Spain. TJ-IU was taken into operation in 1994, and was operated at relatively high magnetic field (0.5 T) and heating power (200 kW of ECRH heating), and corresponding relatively high values of the plasma parameters (electron density: 5 × 10¹⁸ m^-3).

In 1999, TJ-K was transferred to Kiel, Germany, and in 2005 to the IPF institute in Stuttgart, Germany. In its reincarnation as TJ-K, the device is operated at low magnetic field (about 0.07 T) and heating (1-6 kW of ECRH heating), and corresponding relatively low values of the plasma parameters (electron density: 5 × 10¹⁷ m^-3; electron temperature: 10 eV; ion temperature: 1 eV).

Current status

Dense Langmuir probe arrays. The outer port array (OPA, photograph on the left) is installed at the outer port O2 and O3, the top port array (TPA, photograph on the right) is successively installed at the top ports T5, T2 and T4.^[1]

Some research results can be found in the cited papers. ^[2] ^[3] ^[4] ^[5] ^[6] ^[7] ^[8] ^[9] ^[10] ^[11] ^[12] ^[13] ^[14] ^[15]

One of the remarkable diagnostics of TJ-K is a dense array of Langmuir probes, allowing detailed studies of turbulence.

References

[1] G Birkenmeier, M Ramisch, G Fuchert, A Köhn, B Nold and U Stroth, Spatial structure of drift-wave turbulence and transport in a stellarator, Plasma Phys. Control. Fusion 55 (2013) 015003

[2] M. Ramisch, N. Mahdizadeh, U. Stroth, F. Greiner, C. Lechte, and K. Rahbarnia, ρ_s scaling of characteristic turbulent structures in the torsatron TJ-K, Phys. Plasmas 12, 032504 (2005)

[3] N Mahdizadeh, F Greiner, M Ramisch, U Stroth, W Guttenfelder, C Lechte and K Rahbarnia, Comparison of Langmuir and emissive probes as diagnostics for turbulence studies in the low-temperature plasma of the torsatron TJ-K, Plasma Phys. Control. Fusion 47 (2005) 569

[4] M Ramisch, F Greiner, N Mahdizadeh, K Rahbarnia and U Stroth, Observation of large-scale coherent structures under strong E × B shear in the torsatron TJ-K, Plasma Phys. Control. Fusion 49 (2007) 777

[5] N Mahdizadeh, F Greiner, T Happel, A Kendl, M Ramisch, B D Scott and U Stroth, Investigation of the parallel dynamics of drift-wave turbulence in toroidal plasmas, Plasma Phys. Control. Fusion 49 (2007) 1005

[6] P. Manz, M. Ramisch, and U. Stroth, Poloidal mode structure of long-distance correlation of fluctuations under strong E×B shear in the torsatron TJ-K, Phys. Plasmas 16, 042309 (2009)

[7] P. Manz, M. Ramisch, and U. Stroth, Physical Mechanism behind Zonal-Flow Generation in Drift-Wave Turbulence, Phys. Rev. Lett. 103, 165004 (2009)

[8] P Manz, M Ramisch and U Stroth, Experimental estimation of the dual cascade in two-dimensional drift-wave turbulence, Plasma Phys. Control. Fusion 51 (2009) 035008

[9] M Ramisch, P Manz, U Stroth, G Birkenmeier, S Enge, E Holzhauer, A Köhn and B Nold, Non-linear dynamics and plasma flows in a basic toroidal plasma experiment, Plasma Phys. Control. Fusion 52 (2010) 124015

[10] A Köhn, G Birkenmeier, E Holzhauer, M Ramisch and U Stroth, Generation and heating of toroidally confined overdense plasmas with 2.45 GHz microwaves, Plasma Phys. Control. Fusion 52 (2010) 035003

[11] S. Enge, G. Birkenmeier, P. Manz, M. Ramisch, and U. Stroth, Observation of Anomalous Ion Heating by Broadband Drift-Wave Turbulence, Phys. Rev. Lett. 105, 175004 (2010)

[12] P. Manz, M. Ramisch, and U. Stroth, Long-range correlations induced by the self-regulation of zonal flows and drift-wave turbulence, Phys. Rev. E 82, 056403 (2010)

[13] G. Birkenmeier, M. Ramisch, P. Manz, B. Nold, and U. Stroth, Experimental Investigation of the Magnetic Configuration Dependence of Turbulent Transport, Phys. Rev. Lett. 107, 025001 (2011)

[14] P. Manz, G. Birkenmeier, M. Ramisch, and U. Stroth, A link between nonlinear self-organization and dissipation in drift-wave turbulence, Phys. Plasmas 19, 082318 (2012)

[15] G. Birkenmeier, M. Ramisch, B. Schmid, and U. Stroth, Experimental Evidence of Turbulent Transport Regulation by Zonal Flows, Phys. Rev. Lett. 110, 145004 (2013)

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