Initial Result Of Neutron Emission Rate Analysis For Ion Cyclotron Range Of Frequency Heated Deuterium Plasmas In Lhd

A database of the total neutron emission rate (S (n)) in the ion cyclotron range of frequency (ICRF) heated deuterium plasma in the Large Helical Device (LHD) was developed with changing the ICRF injection power and electron density. The S n measured in the experiment was compared with the neutron emission rate calculated by the thermal reactivity of deuterium plasma to predict S n in long-pulse discharge and to understand the heating scheme of ICRF. The ratio of S n evaluated by calculation and that by measurement in the electron cyclotron heating (ECH) and ICRF heating case has almost the same tendency as that of the ECH only case in which energetic deuterons are not expected. In the first campaign of deuterium ICRF plasma discharge with injection power up to 1.5MW, neutron emission with regard to the ICRF tail deuteron was thought to be negligible. We expanded the S n database and started building an S n prediction code to perform a long-pulse deuterium discharge. (C) 2020 The Japan Society of Plasma Science and Nuclear Fusion Research