|
In toroidally confined fusion plasma experiments the term zonal flow means a plasma flow within a magnetic surface primarily in the poloidal direction. This usage is inspired by the analogy between the quasi-two-dimensional nature of large-scale atmospheric and oceanic flows, where zonal means latitudinal, and the similarly quasi-two-dimensional nature of low-frequency flows in a strongly magnetized plasma. Zonal flows in the toroidal plasma context are further characterized by * being localized in their radial extent transverse to the magnetic surfaces (in contrast to global plasma rotation), * having little or no variation in either the poloidal or toroidal direction—they are ''m'' = ''n'' = 0 modes (where and ''m'' and ''n'' are the poloidal and toroidal mode numbers, respectively), * having zero real frequency when analyzed by linearization around an unperturbed toroidal equilibrium state (in contrast to the geodesic acoustic mode branch, which has finite frequency). They arise via a self-organization phenomenon driven by low-frequency drift-type modes, in which energy is transferred to longer wavelengths by modulational instability or turbulent inverse cascade. ==See also== * Zonal and poloidal * Zonal flow * List of plasma (physics) articles 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Zonal flow (plasma)」の詳細全文を読む スポンサード リンク
|