The ion temperature and energy balance in stable discharges in the LT-3 Tokamak

The ion temperature in the Tokamak LT-3 has been deduced from measurements of the thermal Doppler broadening of oxygen impurity line emission from the hydrogen plasma. The profiles of lines in the u.v. region of the spectrum were analysed with a polychromator which measures simultaneously 7 contiguous spectral bands separated by 0.25 A in wavelength. With this instrument, ion temperatures as low as 10 eV could be measured reliably. In stable discharges, which occur in LT-3 only for a sufficiently high q-value at the plasma column boundary, the central ion temperature rises to a maximum of about 30 eV after 4 ms from the initiation of the discharge. The ion energy confinement time at the centre of the discharge reaches a maximum value of about 400 μs. (author)