TJ-IU

The TJ-IU Torsatron

In the torsatron TJ-IU, a single coil generates the helicoidal magnetic field (l=1). The number of turns of the coil around the vacuum chamber is m=6. The vertical field is generated by a set of vertical field coils.

The name 'TJ-IU' arises as this machine was an upgrade ('U') of the TJ-I device, in the sense that much auxiliary equipment from the latter was reused to operate TJ-IU.

Parameter	Value	Unit
Major radius, R0:	0.60	m
Mean plasma radius, a:	0.10	m
Minor coil radius, Rc:	0.24	m
Number of periods, m:	6
Rotational transform at the axis, ι0:	0.30
Magnetic shear:	almost zero
Magnetic well depth:	6.9	%
Magnetic ripple at the axis:	7.6	%
Helical axis elongation:	0.025	m
Toroidal field, BT, at φ=30 degrees:	0.5	T
2nd harmonic Electron Cyclotron Heating, 28 - 37.5 GHz:	200	kW

The making of the TJ-IU vacuum vessel

The device was entirely built in Spain and taken into operation in 1994. In 1999, the device was sent to the University of Kiel, Germany, under a permanent loan agreement, and renamed TJ-K. Currently, TJ-K is located at the University of Stuttgart in Germany.

External links

• STORM: Proposal for upgrading of the TJ-I tokamak to a torsatron device - internal report
• TJ-IU - old web page

References

• L. Pacios, J. Guasp, and J. Vega, A fully programmable data acquisition system for the TJ‐I and TJ‐IU devices, Rev. Sci. Instrum. 63 (1992) 4806
• B.Ph. van Milligen, A. Lopez Fraguas, Expansion of vacuum magnetic fields in toroidal harmonics, Comp. Phys. Comm. 81 (1994) 74
• A.P. Navarro, M.A. Ochando, F. Medina, B.Ph. van Milligen, Local plasma radiation loss rate determination in tokamaks and stellarators, Rev. Sci. Instrum. 66 (1) (1995) 552
• E. Ascasíbar, C. Alejaldre, et al, First results of the TJ-I U torsatron, Transactions of Fusion Technology 27 (1995) 198
• B.A. Carreras, C. Hidalgo, E. Sánchez, M.A. Pedrosa, R. Balbín, I. García-Cortés, B.Ph. van Milligen, D.E. Newman, V.E. Lynch, Fluctuation-induced flux at the plasma edge in toroidal devices, Plasma Physics 3 (7) (1996) 2664
• J. Qin, E. Ascasíbar, A. López-Fraguas, J.A. Jiménez, F. Castejón, T. Estrada, J. Herranz, F. Medina, B.Ph. van Milligen, I. Pastor, J. Sánchez Sanz, TJ-IU Team, Measurements of plasma beta in stellarators, Nucl. Fusion 36 (1996) 381
• M.A. Pedrosa, M.A. Ochando, J.A. Jiménez, R. Balbín, J. Qin, and C. Hidalgo, Magnetic configuration effects on the TJ-IU torsatron plasma edge turbulence, Plasma Phys. Control. Fusion 38 (1996) 365
• Marin, J. Carballo, I. Olmos, P. Ascasibar, E. Pastor, I. Qin, J. Herranz, J. Fraguas, A.L., Real time image integrator for magnetic surface mapping experiments in TJ-I U torsatron, IEEE Transactions on Nuclear Science 43, 1 (1996) 234
• V. Tribaldos and B. Ph. van Milligen, Neural network tool for rapid recovery of plasma topology, Rev. Sci. Instrum. 68 (1997) 931
• E. Ascasibar, J. Qin, A.L. Fraguas, I. Pastor and J. Herranz, Measurement of magnetic surfaces on the TJ-I U torsatron, Nucl. Fusion 37, 6 (1997) 851
• J. Qin, E. Ascasíbar, J.A. Jiménez, A. López-Fraguas, O. Fedyanin, B.Ph. van Milligen, T. Estrada, J. Sánchez Sanz, Diagnostics for measuring equilibrium plasma beta in stellarators, Fusion Engineering and Design 34-35 (1997) 695-699
• C. Hidalgo, M. A. Pedrosa, B. van Milligen, E. Sánchez, R. Balbín, I. García-Cortés, E. Ascasíbar, F. L. Medina, M. A. Ochando, and L. Rodríguez, and the TJ-IU Team, Statistical properties of turbulent transport and fluctuations in the TJ-I tokamak and the TJ-IU torsatron, Plasma Phys. Rep. 23 (1997) 517
• B. Zurro, C. Burgos, K.J. McCarthy, and L. Rodriguez Barquero, Design of luminescent detectors for the TJ-II device, Rev. Sci. Instrum. 68 (1997) 680
• B. Zurro, K.J. McCarthy, E. Ascasíbar, F. Aragón, C. Burgos, A. López and A. Salas, Observation and interpretation of topological structures in impurity ion radiation profiles from the hot plasma of a torsatron, Europhys. Lett. 40 (1997) 269
• F. Castejón, B. Zurro, and A. Cappa, Feasibility study of a method to measure the ECRH field in the plasma interior (abstract), Rev. Sci. Instrum. 68 (1997) 504
• E. Sánchez, C. Hidalgo, M.A. Pedrosa, R. Balbín, B.Ph. van Milligen, I. García-Cortés, Measurement of fluctuation induced flow by multiple Langmuir probes in the TJ-IU Torsatron, Contrib. Plasma Phys. 38 (1998) S, 93
• C. Hidalgo, M.A. Pedrosa, B.Ph. van Milligen, et al, On the radial structure of fluctuations and turbulence induced flows, J. Plasma Fusion Res. SERIES 1 (1998) 96
• E. de la Luna and V. Krivenski, Kinetic effects on Electron Cyclotron Emission during Modulated ECRH in TJ-IU, J. Plasma Fusion Res. SERIES 1 (1998) 354
• F. Medina, L. Rodríguez-Rodrigo, M.A. Ochando and F. Castejón, Superthermal electrons in the TJ-IU torsatron, Plasma Phys. Control. Fusion 40 (1998) 1897
• B.A. Carreras, R. Balbin, B. van Milligen, M.A. Pedrosa, I. Garcia-Cortes, E. Sanchez, C. Hidalgo, J. Bleuel, M. Endler, H. Thomsen, A. Chankin, S. Davies, K. Erents, and G.F. Matthews, Characterization of the frequency ranges of the plasma edge fluctuation spectra, Phys. Plasmas 6 (1999) 4615