The Ultra-Low Aspect Ratio Stellarator SCR-1

The world most compact stellarator is currently being designed at the Costa Rica Institute of Technology (ITCR). The SCR-1(Stellarator of Costa Rica 1) is a 2-field period modular device with a circular cross-section vessel ($R_{o}=0.238m$, $a=0.097m$, $R_{o}$\textit{/a$\approx $2.5}, $0.014m^{3}$, \textit{4mm} thickness 6061-T6 aluminum). The expected D-shaped high elongated plasma cross section has a maximum average radius of $\langle $a$\rangle \approx $0.062m, leading to $R_{o}$/$\langle $a$\rangle \ge $3.8. Such compactness was reached after a SCR-1 earlier proposal [1] was redesigned, both based on the low shear stellarator UST{\_}1: $R_{o}$/$\langle $a$\rangle \approx $6, $\iota $=0.32/0.28 (core/edge) [2]. The set field at centre is 88mT produced by 12 copper modular coils, 8.7kA-turn each. This field is EC resonant at $R_{o}$ with a 2.45GHz $\mu $w, 1$^{st}$ harmonic, from 2/3kW magnetrons which will produce a second time-scale plasma pulse. The coil current will be produced by a bank of cell batteries. Poincar\'{e} and EC deposition plots will be presented using COMSOL Multiphysics software. SCR-1 will be synergetic to the ST MEDUSA currently under donation to ITCR [3]. Both will benefit of the local new activities in technological plasmas.\\[4pt] [1] Barillas L et al., Proc.19$^{th}$ Int.Conf. Nucl.Eng., Japan, 2011\\[0pt] [2] Queral V, Stellarator News, 118, 2008\\[0pt] [3] Ribeiro C et al., 54$^{th}$ APS, Plasma Phys. Div., US, 2012