A torsatron is a magnetic trap in which the magnetic field lines that confine the plasma are wholly formed by coils that are located around the vacuum vessel. These coils are helically shaped and are called helical coils.
In the TJIU Torsatron, the helical field is determined by a single coil, l=1 (yellow). The number of turns that the coil describes around the vessel is m=6. So-called vertical field coils (red), are added in order to avoid that the plasma expands towads th eexternal vessel wall. The form and the position of these coils and the current that passes through them are of critical importance and are defined by means of theoretical calculations. Taking zeta to be the toroidal angle of the torsatron and phi to be th epoloidal angle, then the helical winding law is zeta = 1/6 (phi+0.4 sin(phi)).
The experimental program of this device concentrates essentially on the study of the possible influence of the magnetic shear of the magnetic configuration on turbulent phenomena in the plasma that may affect the particle transport and the energy content of the plasma. Also an attempt is made to control the turbulence through injection of microwaves at the electron cyclotron frequency, modulated at the characteristic frequency of the turbulence and by feedback.
Major radius, R0: 0.6 m Plasma average radius, <a>: 0.10 m Coil minor radius, Rc: 0.24 m Number of periods: 6 Rotational transform at axis: 0.30 Shear: almost null Magnetic well depth: 6.9 % Magnetic ripple at axis: 7.6 % Helical axis elongation: 0.025 m Magnetic field intensity at axis at phi=30 degrees: 0.5 T Heating (ECRH): 200 kW, 28 - 37.5 GHz, 2nd harmonic
iota(0) = 0.23:
iota(0) = 1/3:
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15 degrees
30 degrees
45 degrees