Quasi-Neutrality Breaking in a Rotating Plasma

In this paper, spontaneous quasi-neutrality breaking has been observed in a rotating plasma (plasma hole). Two- dimensional potential measurement revealed that a very high potential ephi/T_e ~ 5 is localized in the region of 1/5 of the plasma radius. Using the Poisson´s equation and fast Fourier transform, we have evaluated the 2-D distribution of the degree of non-neutrality deltan/n, where deltan = n_i-n_e. It is found that deltan/n is three orders of magnitude higher in the hole center than in the peripheral region and that the scale of quasi-neutrality breaking extends over 10³ times the Debye length.