Experimental progress on zonal flow physics in toroidal plasmas

Fujisawa, Akihide*; Ido, Takeshi*; Shimizu, Akihiro*; Okamura, Shoichi*; Matsuoka, Keisuke*; Hamada, Yasuji*; Hoshino, Katsumichi; Nagashima, Yoshihiko*; Shinohara, Koji; Nakano, Haruhisa*; Oshima, Shinsuke*; Miura, Yukitoshi; Ito, Kimitaka*; Ito, Sanae*; Shats, M.*; Xia, H.*; Dong, J. Q.*; Yan, L. W.*; Zhao, K. J.*; Conway, G. D.*; Stroth, U.*; Melnikov, A.*; Eliseev, L. G.*; Lysenko, S. E.*; Perfilov, S. V.*; Hidalgo, C.*; Tynan, G. R.*; Mckee, G. R.*; Holland, C.*; Fonck, R. J.*; Gupta, D. K.*; Diamond, P. H.*

Present status of experiments on zonal flows is overviewed. Innovative use of traditional and modern diagnostics has revealed unambiguously the existense of the zonal flows, their spatio-temporal caracteristics, their relationship with turbulence, and their effects on confinement. Particularly, a number of observations have been accumulated on the oscillatory branch of zonal flows, dubbed geodesic acoustic modes, suggesting necessity of theories to give their proper description. Furthur investigation of relationship between zonal flows and confinement is strongly encouraged as cross-device activity.