Fast Particle Loss-Cone Measurements by the Novel Angular-Resolved Multi-Sightline Neutral Particle Analyzer (ARMS-NPA) on Large Helical Device.

The novel diagnostic of fast particles (ARMS-NPA) based on linear AXUV detector has been successfully developed and started measurements on LHD [1]. This is the first time of using AXUV detector for fast particle measurements on plasma devices. ARMS-NPA can provide time-, angular- and energy-resolved measurements of fast particles even in short-time discharges. This diagnostic can be a powerful tool in fast particle physics and confinement studies in such a complex helical plasma geometry like the one of LHD. It can become irreplaceable instrument in the checking of fast particle loss-cones existing in helical devices which were predicted by some theoretical works [2,3] and refuted by another [4]. Measurements were made in the variety of experimental conditions and compared with theoretical simulations. [1] E.A. Veshchev, T.Ozaki, \textit{et al.}, Rev. Sci. Instrum., \textbf{77}, 10F129-1 (2006) [2] H.Sanuki, J.Todoroki and T.Kamimura. Phys. Fluids B \textbf{2 }(9), 2155 (1990) [3] M. Wakatani, \textit{Stellarator and Heliotron Devices }(Oxford University Press, Oxford, 1998) [4] T. Watanabe \textit{et al.}, Nucl. Fusion \textbf{46}, 291 (2006).