B33 Fieldreversed configurations

Compact toroids are configurations characterized by the absence of a mechanical structure shaping the plasma. The configuration is "compact", in the sense that plasma extends to the geometrical axis, and "toroidal", in the sense that the topology of the closed magnetic surfaces is that of a torus (Figure B.14). Compact toroids can therefore combine the good confinement properties of closed toroidal configurations with the simple topology of open magnetic field systems. Compact toroids consist of two distinct regions:

— a closed field line region inside a magnetic separatrix, with radius rs;

— an open field line sheath outside the separatrix.

Plasma is well confined inside the separatrix and exhausted through the open field line region.

Compact toroids can be classified according to the following two parameters:

— the ratio between the poloidal magnetic field B, in the (r, z) plane, and the toroidal magnetic field B0 (along 0);

— the parameter (usually denoted by S) corresponding to the number of ion gyro-radii between the field null and the separatix. This parameter is related to the inverse of the p* parameter.

The table immediately below shows such a classification:

0 0

Post a comment