Plasma edge cooling by impurity radiation in a tokamak
Impurities are used to establish a cold radiative plasma boundary in high power discharges. Neon proves to be a promising candidate. In TEXTOR a neon injection feed-back system has been applied successfully to control the radiation level; up to 95 % (gamma = 0.95) of the heating power has been radiated in stable and quasi-stationary discharges. Above gamma approximately equal to 0.7 suppression of thermal condensation effects (Marfes) is necessary and, in principle, possible. Neon cools the plasma edge and not the centre (radiative range at T(e) approximately equal to 30-200 eV). The crucial limitation for radiative edge cooling is given by the impurity concentration in the centre. For neon 2 MW of radiation is possible (0.25 MW/m3) with n(Ne)/n(e) approximately equal to 0.7 % in the centre, which is marginally acceptable for fuel dilution.
Bibliographic Reference: Article: Plasma Physics and Controlled Nuclear Fusion Research 1992, Vol. 1 (1993) pp. 309-315
Record Number: 199311257 / Last updated on: 1994-11-29
Original language: en
Available languages: en