NIFS

Research Report2021

LHD Research report December 14, 2021
Good core plasma performance realized in deuterium plasmas compatible with heat load mitigation at the plasma facing components

In a deuterium plasma experiment in large helical device (LHD), we have succeeded in reducing the excessive heat load on the device wall while maintaining the performance of the confined plasma. ...

Press Release November 5, 2021
Impact of Magnetic Field Configuration on Suppression of Turbulence

In order to realize fusion power generation, high-temperature plasma*1 must be confined by a magnetic field. ...

LHD Research report August 17, 2021
Advances in Understanding Energetic Ion Transport by Magnetic Field Oscillations

In future fusion burning plasmas, there is a concern that energetic alpha particles may escape due to magnetic field oscillations caused by the pressure of alpha particles, which is the main heating source of the plasma. ...

LHD Research report August 2, 2021
First observation of characteristic fine structure of global plasma fluctuations

In magnetic confinement plasmas, the rapid growth of temperature fluctuations after their rotation stops is a problem, and a new measurement technique at the LHD has successfully measured the fine structure of temperature fluctuations during the slowing-down of the rotation. ...

LHD Research report July 14, 2021
Spectral line identifications of highly charged praseodymium and neodymium ions in LHD

https://www-lhd.nifs.ac.jp/pub/Science_en/Paper_ATOMS9-46.html ...

LHD Research report July 7, 2021
Improved measurement of the effective ion charge represented the amount of impurities in the plasma

We have improved the measurement of the effective ion charge (Zeff), which represents the amount of impurities in the plasma in the Large Helical Device (LHD). ...

LHD Research report June 16, 2021
A new method for simultaneously injecting different impurities into the plasma

In a tracer-capsulated solid pellet (TESPEL) scheme, which is a technique for locally depositing impurities to the desired location in high-temperature plasmas, we have developed a new method for injecting multiple impurities, which is completely different from the previous method. ...

LHD Research report June 2021
Prediction of Unusual Emission of Visible Light in Plasma Experiments by using Machine Learning

In plasma experiments at the Large Helical Device (LHD), an unusual emission of visible light inside the plasma vessel has been observed. ...

Press ReleaseEurekAlert! June 9, 2021
Developing the novel joint technique for copper alloy: This highly contributes to producing the efficient heat removal component for fusion reactor

The oxide dispersion strengthened copper alloy (ODS-Cu) is superior in thermal conductivity, electrical conductivity, heat resistance and friction tolerance, etc. ...

LHD Research report April 28, 2021
Measuring the spatial distribution of energetic particles in a plasma

In future fusion plasmas, energetic particles produced by fusion reactions will heat the plasma and maintain a high temperature and density. ...

LHD Research report April 21, 2021
Analysis of NB Beam-Ion Loss Mechanisms in LHD

The beam ion loss mechanism in the Large Helical Device (LHD) has been analyzed quantitatively by using neutron measurement and integrated simulation*. ...

LHD Research report April 14, 2021
Advances in the understanding of pellet injection as a plasma diagnostic technique

The technique of injecting small solid materials called “pellets” into high-temperature plasma is indispensable for fueling and maintaining plasma performance in future fusion reactors. ...

LHD Research report April 13, 2021
Development of new instrument for micro-scale turbulence observation

We have developed an instrument to measure the micro-scale turbulence in high temperature plasmas with high accuracy. ...

Press ReleaseEurekAlert! March 31, 2021
Development of a broadband mid-infrared source for remote sensing

A research team of the National Institutes of Natural Sciences, National Institute for Fusion Science and Akita Prefectural University have successfully demonstrated a broadband mid-infrared (MIR) source with a simple configuration. ...

LHD Research report March 12, 2021
Development of High-Performance Millimeter-Wave Filters for Diagnostics of Internal Structure of Ultra-High-Temperature Plasmas

In fusion reactors, millimeter-wave megawatt electromagnetic waves are used to heat the plasma to 100 million degrees Celsius, where a fusion reaction occurs. ...

LHD Research report March 05, 2021
Identification of the criteria for the plasma collapse discharge in helical plasmas

In the LHD, the plasma discharges, with the cases predicted to be unstable in MHD instabilities before construction, are maintained without any collapse phenomena. On the contrary, in the discharges predicted to be very unstable in theory, the collapse phenomena are observed. ...

LHD Research report February 26, 2021
Control of energy output from fusion plasma

In a future fusion reactor, energy will be produced by deuterium and tritium reactions. We can control the fusion output by changing the plasma parameters such as density and heating power. ...

LHD Research report February 26, 2021
Development of standard neutron flux monitor for fusion research

The Large Helical Device (LHD) has been conducting plasma discharges using deuterium gas, so-called deuterium experiments, since March 2017 to improve plasma performance. ...

LHD Research report February 12, 2021
First observation of degradation of confinement and reversal of plasma flow due to broken confinement magnetic field

High-temperature and high-density plasma should be maintained in the fusion reactor vessel with a high confinement state. ...

LHD Research report February 10, 2021
Remote Experiment from the Opposite Side of the Earth

Technical verification has been progressing for high efficiency data replication between ITER and the Remote Experimentation Centre (REC) in Japan. ...

LHD Research report January 31, 2021
Data location informing service to quickly find out the data distributed in remote sites

The ITER Remote Experimentation Centre (REC) in Japan is planning to replicate all the data, as fast as possible, from ITER in France which is more than 10 000 km away. ...

LHD Research report January 22, 2021
Construction of the measuring system for plasma heat flux to the wall

Significant heat flux is expected at the wall called “the divertor plate” in the fusion device. The present study constructed the system for measuring the divertor heat flux by 2 dimensional (2D) thermography and thermal conduction analysis in the Large Helical Device (LHD). ...