Current filaments in plasmas

Possible configurations of current filaments in Z-pinch and tokamak plasmas are analyzed. A thin current-carrying beam injected in a plasma should be surrounded by a halo of countercurrents, in which case the resulting configuration may resemble a tubular structure. A.B. Kukushkin and V.A. Rantsev-Kartinov pointed out the existence of specific plasma structures of the squirrel-cage type and interpreted them as “wild cables of solid-state nanotubes.” It is shown that these structures can also be attributed to the fundamental mode of the conventional magnetic filamentation in the form of a “hexagonal parquet.” Also, a study is made of the phenomena governing the pattern of plasma structures, namely, tearing filamentation, two types of longitudinal beam bunching, and self-organization of the filaments.