It is proposed to expand the outermost flux surfaces in tokamaks to divert the heat flux emerging from the plasma core. The approach previously discussed in detail is to deform the poloidal field configuration for expansion of the boundary. A simpler approach is discussed here which does not require any coil system or power supply, an attractive feature for reactor application.
Centripetal propagation of low frequency waves of f_??_20-30 MHz are observed in a linear turbulently heated plasma, using a 70 GHz microwave scattering. The scattered radiations are detected with a heterodyne detection system which has a feedback-loop for stabilizing the difference frequency between the incident and local ones. A narrow spectrum which is initially observed and corresponds to the waves propagating toward the axis of the cylindrical plasma, tends to spread toward low frequency region, and in a later time an approximately symmetrical distribution is realized.
Self reversal of axial magnetic fields appearing in a stabilized linear Z-pinch has been investigated. Photographical observation confirmed the self reversal associated with the helical kink instability of a short wavelength. The reversal of magnetic fields did not occur when plasma columns were dynamically stabilized by superposing RF currents on DC plasma currents.