RF plasma heating in the Uragan stellarator. II. Thermal isolation and particle containment

Recent stellarator research

“…36). It was shown that the ion energy life-time was in satisfactory agreement with the value calculated from neoclassical theory [217]. RF heating experiments were continued in Uragan-2[160].…”

“…Longer RF pulses lead to a neutral-particle influx, which tends to constrict the" current channel and leads to MHD instabilities. In the Heliotron D, an RF coil similar to the Kharkov type [216,217] was used for ICRH in an Ohmically heated plasma. A heating efficiency of 10-20% was observed in the range of n e = 5 X 10 12 ~ 5 X 10 13 cm" 3 , which was in agreement with other experimental results [241,243].…”

Effect of drift modes on currentfree plasma transport processes in a stellarator

“…In virtually all the experiments conducted so far on the toroidal confinement of a plasma there has been observation of anomalous losses of heat and particles [1][2][3][4][5][6][7]. Their magnitude is 10-100 times greater than the neoclassical values calculated on the basis of binary collisions alone.…”

“…Subsequent experiments demonstrated that the pseudoclassical relationship for losses of relatively low-density plasma 1 was of a more general nature and applied not only to tokamaks but sometimes also to stellarators with a current [2][3][4][5][6][7], and under conditions of currentfree plasma confinement [9].…”

“…As far as the confinement of particles is concerned, detailed experimental studies with stellarators (Uragan-1 [2], Uragan-2 [15], Cleo [5], Wendelstein H-b [3], Heliotron-D [16], etc.) have demonstrated that in terms of its type of dependence on discharge parameters turbulent diffusion is similar to neoclassical diffusion for the plateau, while in absolute terms it may differ from it by more than one order, depending on the current drift velocity (see, for example, the results of the Torso experiments [5]).…”