DD Fusion neutron measurements in the beam-heated stellarator deuterium plasmas on Heliotron E

This paper describes the measurement of D-D fusion neutrons in the toroidal stellarator plasmas on Heliotron E. We used three moderated 3He counters and a moderated BF3 counter. Calibration of neutron detectors was previously done with a 252Cf spontaneous fission neutron source. We describe the measured fusion neutron emissions with several discharge conditions with hydrogen neutral beam injection heating to the deuterium plasmas. The Heliotron E plasmas are usually initiated by electron cyclotron resonance heating at a magnetic field of 1.9 T without an ohmic heating plasma current. We have tried to deduce the central deuterium ion temperature from measured neutron flux and line-averaged electron density. We have compared the central ion temperatures by neutron flux, with the passive charge exchanged particle analyses and diamagnetic stored energy. We discuss the possible error sources for the central neutron deduced deuterium temperature.