The Theories of Turbulence in the Periphery of Thermonuclear Devices

✍ Scribed by A. V. Nedospasov

• Publisher: John Wiley and Sons
• Year: 1992
• Tongue: English
• Weight: 246 KB
• Volume: 32
• Category: Article
• ISSN: 0005-8025
• DOI: 10.1002/ctpp.2150320323

✦ Synopsis

The review contains the principal results of the theoretical investigations of the edge turbulence in tokamaks, stellarators and mirror machines.

Different models based on the dissipation due to Coulomb collisions were developed to explain the edge turbulence. For example, the rippling instability including the toroidal effects and the diamagnetic current has been used for the description of edge turbulence in tokamaks. The instabilities of plasma in the scrape-off layer of a poloidal or toroidal limiter including a flute instability with the current flow to the limiter surface are surveyed.

An instability driven by the electron temperature gradient was found for a plasma in contact with a conducting wall in mirror machines also. Arguments in favour .of the dissipation due to the current flowing through a potential sheath near the wall as a mechanism for edge turbulence are presented.

The theoretical models are compared with the experimental data.

The dissipation mechanism is known to be the most important mechanism in the processes of plasma transport across the confining magnetic field. Mechanical work due to plasma expansion in its convective or diffusive motion to the wall is converted into electrical energy. Classical diffusion in homogenous magnetic field or Pfinch-Schloter convection are well-known examples for the volume dissipation by collision. Anomalous diffusion calls for anomalous (collision-free) dissipation due to turbulence. However, in addition to "volume" dissipation (VD) "surface" dissipation (SO1 is