Plasma and Fusion Research

Volume 15, 1202088 (2020)

Rapid Communications

Initial Result of Neutron Emission Rate Analysis for Ion Cyclotron Range of Frequency Heated Deuterium Plasmas in LHD
Ryosuke SEKI1,2), Shuji KAMIO1), Hiroshi KASAHARA1), Kenji SAITO1), Tetsuo SEKI1), Kunihiro OGAWA1,2), Mitsutaka ISOBE1,2), Hideo NUGA1), Hiromi TAKAHASHI1), Shin KUBO1,3), Masaki OSAKABE1,2) and LHD Experiment Group
1)
National Institute for Fusion Science, National Institutes of Natural Sciences, Toki 509-5292, Japan
2)
The Graduate University for Advanced Studies, SOKENDAI, Toki 509-5929, Japan
3)
Nagoya University, Nagoya 464-8601, Japan
(Received 25 August 2020 / Accepted 3 November 2020 / Published 11 December 2020)

Abstract

A database of the total neutron emission rate (Sn) 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 Sn measured in the experiment was compared with the neutron emission rate calculated by the thermal reactivity of deuterium plasma to predict Sn in long-pulse discharge and to understand the heating scheme of ICRF. The ratio of Sn 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 1.5 MW, neutron emission with regard to the ICRF tail deuteron was thought to be negligible. We expanded the Sn database and started building an Sn prediction code to perform a long-pulse deuterium discharge.

Keywords

neutron emission rate database, ICRF, second harmonic heating, minority proton heating, LHD

DOI: 10.1585/pfr.15.1202088

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