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Physical Sciences and Mathematics Commons

Open Access. Powered by Scholars. Published by Universities.®

Statistical, Nonlinear, and Soft Matter Physics

Dartmouth Scholarship

Series

Instability

Publication Year

Articles 1 - 2 of 2

Full-Text Articles in Physical Sciences and Mathematics

Turbulence And Bias-Induced Flows In Simple Magnetized Toroidal Plasmas, B. Li, B. N. Rogers, P. Ricci, K. W. Gentle May 2011

Turbulence And Bias-Induced Flows In Simple Magnetized Toroidal Plasmas, B. Li, B. N. Rogers, P. Ricci, K. W. Gentle

Dartmouth Scholarship

Turbulence and bias-induced flows in simple magnetized toroidal plasmas are explored with global three- dimensional fluid simulations, focusing on the parameters of the Helimak experiment. The simulations show that plasma turbulence and transport in the regime of interest are dominated by the ideal interchange instability. The application of a bias voltage alters the structure of the plasma potential, resulting in the equilibrium sheared flows. These bias-induced vertical flows located in the gradient region appear to reduce the radial extent of turbulent structures, and thereby lower the radial plasma transport on the low field side.


High-Latitude Propagation Studies Using A Meridional Chain Of Lf/Mf/Hf Receivers, J Labelle Apr 2004

High-Latitude Propagation Studies Using A Meridional Chain Of Lf/Mf/Hf Receivers, J Labelle

Dartmouth Scholarship

For over a decade, Dartmouth College has oper- ated programmable radio receivers at multiple high-latitude sites covering the frequency range 100–5000 kHz with about a 1-s resolution. Besides detecting radio emissions of auro- ral origin, these receivers record characteristics of the iono- spheric propagation of natural and man-made signals, docu- menting well-known effects, such as the diurnal variation in the propagation characteristics of short and long waves, and also revealing more subtle effects. For example, at auroral zone sites in equinoctial conditions, the amplitudes of dis- tant transmissions on MF/HF frequencies are often enhanced by a few dB just before …